Nobody likes to dwell on what might go wrong, but if you’re considering dermal fillers, it’s important to go in with your eyes open. Most treatments go smoothly, but side effects can happen, and in rare cases, complications can be serious.
Here’s an honest look at what can go wrong, which areas carry the most risk, and how to protect yourself.
The most common downsides
These are the side effects most people experience to some degree. They’re temporary and manageable, but worth knowing about.
Swelling, bruising, tenderness
Swelling and bruising are almost guaranteed, especially in more sensitive areas like the lips. Tenderness at injection sites is normal for a few days. Most of this settles within a week, though some puffiness can linger for up to two weeks. It’s inconvenient, but it’s not dangerous.
Lumps & unevenness
Lumps are surprisingly common in the first few days after treatment. They’re usually caused by the filler settling unevenly or minor swelling around the injection site. Most smooth out on their own within a week or two. If they don’t, your injector can massage them or, in some cases, dissolve the filler with hyaluronidase. Persistent lumps can also be a sign the filler was placed too superficially or that your body is reacting to it.
Overfilling
This is more about technique than complication, but it’s worth mentioning. Overfilling happens when too much product is used or when filler is placed in the wrong tissue plane. The result? A puffy, unnatural look. Sometimes this improves as swelling goes down, but if it doesn’t, the filler can be dissolved. This is why starting conservatively and building up over sessions is always the smarter approach.
Rare but serious complications
These complications are uncommon, but they’re the reason you need a qualified, experienced injector who knows how to handle emergencies.
Infection
Any time a needle breaks the skin, there’s a small risk of infection. Signs include increasing redness, warmth, pain, and sometimes pus at the injection site. Infections need prompt treatment with antibiotics. They’re rare if proper sterile technique is used, but they can happen.
Vascular occlusion
This is the most serious complication. It happens when filler accidentally blocks a blood vessel, cutting off blood supply to the surrounding tissue. Symptoms include severe pain, skin turning white or mottled, and in extreme cases, tissue death or vision loss if it affects vessels near the eyes. It’s a medical emergency. The good news? It’s rare, and if caught early and treated with hyaluronidase (which dissolves the filler immediately), the outcome is usually fine. This is why your injector must know facial anatomy inside out.
Inflammatory reactions
Granulomas are hard lumps that form when your immune system reacts to the filler as a foreign body. They can appear weeks or even months after treatment. They’re uncommon but can be stubborn to treat, sometimes requiring steroids or even surgical removal. Inflammatory reactions can also occur with certain filler types or if the product isn’t stored or handled correctly.
The riskiest areas for fillers
Not all facial areas carry the same level of risk. Some zones have more complex anatomy or are closer to major blood vessels, making complications more likely.
Nose
The nose is one of the highest-risk areas for filler. The blood vessels here are delicate and end arteries, meaning if one gets blocked, there’s no backup blood supply. Vascular occlusion in the nose can lead to skin necrosis (tissue death) or, in the worst cases, blindness if filler travels to the retinal artery. Non-surgical rhinoplasty should only be performed by highly experienced injectors who understand the anatomy and can manage complications immediately.
Tear trough & under-eye
The skin under the eyes is incredibly thin, and the area sits close to important blood vessels. There’s also a risk of the Tyndall effect, where filler placed too superficially causes a bluish tinge under the skin. Lumps are harder to hide here, and vascular complications, though rare, can be serious. It’s a technically demanding area that requires precision.
Forehead and temples
The forehead and temples have major blood vessels running through them, including the supratrochlear and supraorbital arteries. Filler injected here carries a risk of vascular occlusion, which can affect blood flow to the skin or, in rare cases, the eyes. Only very experienced injectors should work in these areas.
Glabella
The glabella, the area between your eyebrows, is another high-risk zone. It’s rich in blood vessels that connect to the ophthalmic artery, which supplies the eyes. Accidental injection into these vessels can lead to blindness. It’s not common, but it’s serious enough that many injectors avoid placing filler here altogether or use extreme caution.
How to reduce risk
You can’t eliminate risk entirely, but you can drastically reduce it by being smart about who treats you and how.
Choosing a qualified injector
This is the single most important thing you can do. Your injector should be a qualified healthcare professional: a doctor, dentist, or nurse prescriber with extensive training in facial anatomy and injectable treatments. Check their qualifications, ask how long they’ve been injecting, and look at before-and-after photos. If they can’t manage complications or don’t have hyaluronidase on hand, that’s a red flag.
Patch-test expectations
Patch tests aren’t routinely offered for hyaluronic acid fillers because allergic reactions are extremely rare. However, if you have a history of severe allergies or have reacted to fillers in the past, it’s worth discussing with your injector. For non-hyaluronic acid fillers (like Sculptra or Radiesse), a patch test may be more relevant.
Documentation and aftercare plan
Your injector should record the brand, batch number, and amount of filler used in your medical notes and give you a copy. This is essential if you ever need the filler dissolved or if there’s a product recall. You should also leave with clear aftercare instructions and an emergency contact number. If something goes wrong, you need to be able to reach someone immediately.
What symptoms warrant same-day contact
Contact your clinic immediately if you experience severe pain that’s getting worse, not better. If your skin turns white, blanched, or mottled, or if you notice any vision changes (blurriness, loss of vision, double vision), these are emergency symptoms. Similarly, if you develop signs of infection (increasing redness, heat, swelling, or pus), get in touch straight away. Don’t wait to see if it improves. Early intervention can prevent serious complications.
