What to Expect After a Treatment

Telling the Expected from the Unexpected

Not every symptom after an injection carries the same weight. Some are simply the mark the needle and the product leave in the tissue; they settle on their own and do not mean that anything has gone wrong. A much smaller number are a sign that blood is not reaching the tissue; in that case, waiting is not the right thing to do.

An article cannot tell you what your own symptom means; the doctor who sees you assesses that. What it can do is explain which group a symptom belongs to and why it is placed there.

Side effects after filler are first sorted by when they appear. In expert consensus recommendations, treatment also starts from this distinction in timing: a problem that appears early and one that appears months later are not the same thing, even if they look alike.

A review that brings together studies with a high level of evidence divides side effects into three groups: expected reactions, side effects related to the product or the technique, and serious side effects.

Expected Symptoms at the Injection Site

The US Food and Drug Administration (FDA) lists the common risks of fillers one by one: bruising, redness, swelling, pain, tenderness, itching and rash. These are not exceptions; they are known to come with the procedure.

A review of side effects from hyaluronic acid (HA) injections in the face shows a similar picture: the most frequently reported effect is bruising; oedema (swelling caused by fluid building up in the tissue) is also frequently reported, while itching is reported much less often. Ischaemia (when tissue is not getting enough blood) also appears near the top of the same list. But the reason for this lies in the type of studies reviewed, not in how often ischaemia occurs: most of these studies are case reports or case series, and rare, severe cases are more likely to be published. In other words, this ranking does not show how often each problem occurs; it shows which problems are published more often.

The cause of these symptoms is simple. The needle passes between small blood vessels under the skin, and touching some of them causes bruising. The tissue responds with fluid both to the small injury caused by the needle and to the newly placed volume; this is where the swelling comes from. Redness and tenderness are the visible signs of a temporary inflammatory response in the area.

What these symptoms have in common is that, although they can be uncomfortable, they do not get worse.

The Typical Course of These Symptoms

According to a review that brings research together, most side effects are short-lived reactions at the injection site that go away on their own; they usually clear up within weeks without treatment. Serious side effects are rare; they can last for months and need effective medical treatment.

It would not be right to give a single number for how many days these symptoms last. How long they last depends on the treated area, the type of product used and how your tissue responds. This is also why the figures in different studies do not match. The doctor who carries out your treatment will tell you how long your symptoms are expected to last.

There is a more reliable measure than a number: the direction the symptoms are moving in. In the expected course, symptoms are decreasing. Swelling, redness and tenderness are a little less each day than the day before; a bruise changes colour as it fades. As long as they keep moving in this direction, the picture stays within the expected group.

When the direction reverses, meaning a symptom that should be decreasing starts to increase instead, this is no longer the same situation.

Symptoms Outside the Expected Range

The FDA’s warning to patients is clear and short: if you notice unusual pain, changes in your vision, skin near the injection site that looks white, grey or blue, or signs of a stroke during or immediately after the procedure, get medical help without delay. Signs of a stroke include:

• Sudden difficulty speaking
• Numbness or weakness in the face, arms or legs
• Difficulty walking
• Changes in vision
• Drooping of the face
• Severe headache
• Dizziness
• Confusion

The same agency gives a matching instruction to the person giving the injection: the injection is stopped as soon as blanching, a change in vision, a sign of a stroke or unusual pain appears. So these signs are not only a list you are told about afterwards; they are also a rule for stopping the injection during the procedure.

The logic of this list is proportion. Some pain is expected after the procedure; what is not expected is pain that is out of proportion to the size of the procedure. Some discolouration is also expected; what is not expected is blanching or a vivid purple-blue discolouration that suggests the tissue is not getting blood. No symptom affecting vision belongs in the expected group.

The practical test is this: expected symptoms ease over time; blanching and pain that is out of proportion do not. If these two occur together, the right decision is not to wait but to seek help.

What Vascular Occlusion Does to Tissue

Behind these warning signs lies a single condition. The FDA describes it as the most concerning risk of fillers: the filler being injected into a blood vessel by accident, the vessel becoming blocked and the tissue losing its blood supply. The chance of this happening is low; but if it does happen, the consequences can be severe and permanent. Reported consequences include tissue death, vision problems including blindness, and stroke.

According to a review of vascular occlusion (a blocked blood vessel) caused by hyaluronic acid (HA) fillers, recognising the problem early is decisive in limiting further tissue damage. The key word here is ‘early’: the time that passes directly affects how much tissue can be saved. There is also an important limit on the prevention side: a ‘pull-back’ test before injecting (drawing back the syringe plunger to check whether the needle has entered a blood vessel) is debated, and it cannot reliably rule out that the needle is inside a blood vessel. In other words, no technical precaution reduces this risk to zero; this is why early recognition is so important, alongside prevention.

A guideline on the subject divides the progression of tissue ischaemia (the tissue being left without blood) into identifiable stages. These stages help to assess how far the lack of blood supply has spread and how much time has passed since it began. Their importance comes from showing that the condition does not stand still; it progresses over time.

This condition is now also a concern for emergency departments. A review written in this field treats vascular occlusion caused by cosmetic filler as a vascular emergency caused by a medical procedure (iatrogenic) that brings patients to the emergency department; early recognition and correct referral are considered the first step of care.

Why Vision Symptoms Are Treated Separately

Vision loss is a rare but devastating consequence of filler treatments. A guideline prepared by consensus by a working group that brings together different specialties approaches the subject in exactly this way and groups its recommendations under four headings:

• Emergency measures to take straight away
• Routes to specialist care
• Improving informed consent (giving the patient information and obtaining their agreement before the procedure)
• Raising awareness of complications affecting vision

The second of these headings concerns you directly. How to reach specialist care should be clear before the procedure; it is not something to work out after a vision symptom has appeared. The question to ask is: in that situation, who will be contacted, how, and how quickly?

In practice, this means that no symptom affecting your vision should be left until the next day. Blurred vision, loss of part of your field of vision, double vision, or sudden, severe pain around the eye are not among the expected symptoms.

Why Heat, Strenuous Exercise and Alcohol Are Limited Early On

All three recommendations have the same reason behind them: anything that increases blood flow to the skin can make bruising and swelling more noticeable in the early period. This is why hot environments, strenuous exercise and alcohol are mentioned together; all three widen the blood vessels.

You can also see from the other side of the subject that heat really does affect blood vessels: in the initial treatment of vascular occlusion, applying heat and massage are among the methods used alongside hyaluronidase (a substance that dissolves hyaluronic acid filler). There, the aim is to increase blood flow. Straight after an injection, however, this effect is not wanted, because increased blood flow at that point only increases swelling and bruising.

It is important to be open about the scientific basis of this advice. A set of recommendations prepared for injectable treatments lists avoiding alcohol and medicines that increase bleeding among the precautions to take before the procedure; but it also notes that research findings do not agree on products applied to the skin and on skincare before and after the procedure.

An expert consensus document on the risk factors for problems that appear later also lists aftercare as one of four risk headings, and reaches the same conclusion for all of them: most current recommendations are not supported by strong clinical evidence. In other words, this advice is sensible and widely given, but it does not rest on solid research.

This is why it would not be right to give a set number of days for the ‘early period’. How long the restrictions last depends on the treated area, the product used and how your tissue responds; the doctor who carries out your treatment will tell you the period that applies to you.

Delayed-Onset Nodules

If the first few days after an injection go smoothly, people tend to think the matter is closed. But the scientific data do not support this assumption. The FDA clearly states that effects of filler injections can appear weeks, months or even years later. According to the agency’s warning, raised nodules (small firm lumps) in or under the skin and granulomas (clusters of inflamed tissue formed by immune cells) may need treatment with injections, antibiotics taken by mouth, or removal by surgery.

According to expert consensus on delayed-onset reactions, these problems usually appear months after the injection, and sometimes within the first day. The experts describe three possible mechanisms. The first is the physical and chemical structure of the product; in particular, it has been suggested that low-molecular-weight hyaluronic acid may trigger an immune response. The second is infection: bacteria that entered during the injection, or were lying dormant in the body, becoming active. The third is a change in the person’s immune balance; autoimmune diseases and viral infections fall under this heading.

This third mechanism explains something patients often think is a coincidence. Recent dental treatment, your health at the time and an active autoimmune disease are listed among the personal risk factors. The FDA also states that swelling or redness near the injection site can develop after viral or bacterial illnesses, infections, vaccinations or dental procedures.

Another study on late inflammatory reactions lists the same triggers and recommends a step-by-step approach to treating these reactions. The practical point for you is this: swelling or a firm lump that appears months later, especially after a flu-like illness, a vaccination or a dental procedure, is a known pattern and needs to be assessed. You should not assume that it will go away on its own.

Infection and Biofilm

Some of the problems that appear later are caused by infection, and infection cannot always be easily told apart from a nodule. In a retrospective study of filler complications seen at a single clinic over a set period, most cases were nodules and persistent inflammatory reactions; some were active infections. Bacteria grew from some of the tissue samples taken, and these included staphylococcal species. The researchers concluded that biofilm formation is a significant risk factor for late and delayed complications; in their view, it comes from contamination with bacteria that normally live at the injection site and from an infection that progresses slowly without obvious signs.

A biofilm is a structure in which bacteria attached to a surface live beneath a coating they produce themselves. Expert consensus recommendations treat biofilm as a separate category of filler complication, and state that this possibility should be taken into account when treating nodules and persistent inflammation.

The FDA also lists infection, open or draining wounds, and sores forming at the injection site among the reported risks. The deciding question is this: if the area is getting warm, the redness is spreading, the pain is increasing or there is discharge, this should no longer be seen as swelling but as a possible infection; it is not something to monitor on your own.

Why Timing Is Decisive

Every distinction between expected and unexpected symptoms rests on a single axis: time. In expert consensus recommendations, filler complications are classified by when they appear, and treatment is planned according to this classification. Symptoms that appear within the first few hours suggest a problem with a blood vessel; symptoms that appear weeks or months later point to inflammation, the immune system or infection.

Hyaluronidase, which is used to reverse the effect of hyaluronic acid (HA) fillers, is used in some of these situations. According to a review of the subject, it is used for vascular occlusion, blindness, hypersensitivity reactions, delayed-onset nodules and unwanted aesthetic results. But the evidence does not support all of these uses equally: evidence from randomised trials (studies in which participants are divided into groups at random) is limited to dissolving uncomplicated filler nodules placed in the skin of the arm and back. There is no evidence at this level for reversing treatments in the face, correcting excess filler, inflammatory nodules or tissue ischaemia.

What this means for you is this: the fact that your filler was done with a product that can be reversed is not a reason to wait. Having a way to reverse it does not make time less important; it makes it more important. Dissolving filler is a separate treatment; you can find the details on the Filler Dissolving page.

Treatments Offered Here

This clinic offers hyaluronic acid (HA) fillers, collagen-stimulating fillers, thread lifts with dissolvable threads, botulinum toxin (often called Botox®), mesotherapy and filler dissolving. The scope and limits of each treatment are explained separately on its own page: see the Liquid Facelift with Collagen Stimulators page for liquid facelifts and the Filler Dissolving page for dissolving filler.

This guide explains which symptoms are expected and which are not; it cannot tell you which one you have. If you notice one of the warning signs, what you need to do is not decide for yourself but contact the doctor who carried out your treatment. On everything else, there is no need to rush: you now have the criteria for when to seek help, and the timing is your choice.