Key takeaway: When it comes to side effects from fillers, the problem isn't the product itself, but where the needle goes. The decision to avoid blood vessels and inject only into the necessary layer determines safety, and collagen boosters are not exempt from this principle.
Why are inflammation and necrosis mentioned specifically?
The reason the word "necrosis" is associated with fillers is due to blood vessels. Beneath the face, thick and thin blood vessels run in layers, and their paths and depths vary slightly from person to person.
If the tip of the needle enters a blood vessel, or if the injected amount presses on a blood vessel, the blood flow to the area below it is blocked. Tissues cannot survive if their blood supply is cut off. This is why concerns often arise in areas with dense blood vessels, such as the nose, lips, chin, and aegyo-sal.
It is true that hyaluronic acid filler is considered a relatively easy material to handle. It is a component naturally found in the body, and if problems arise, there is an enzyme that can dissolve it. However, this is only true if it was injected into the correct place to begin with.
A question that precedes the product name
Which brand to use is often the first topic of discussion during a consultation, but what truly determines the outcome comes after that. It's about understanding where the blood vessels flow in the face, avoiding dangerous areas, and injecting only into the necessary layer.
This is an area of anatomy before it is a matter of technique. Even with the same product, if the layer is different, both the shape and safety will change. Therefore, it is important to ask not just what is being used, but how it is being injected.
Learn the differences between filler vs. Rejuran vs. Juvelook
Are collagen boosters an exception?
There are some who feel uncomfortable with fillers and are leaning towards boosters. They might think that since boosters work by stimulating the body's own collagen production rather than simply filling, they might be safer.
This is only half true. Boosters are also procedures that involve injecting something into the skin with a needle. If there are blood vessels in the path, the risk is the same, and if the wrong layer is targeted, it can lead to nodules or inflammation.
Safety is not determined by the material, but by how accurately one understands the layered structure of the skin and how carefully the procedure is approached.
What to check during a consultation
Asking "Is this product safe?" alone won't tell you much. Instead, looking into these things can be helpful: whether the doctor explains the skin thickness or the layer to be injected, whether they check the position of blood vessels and muscles by hand during the procedure, and how post-procedure care is managed.
No procedure is entirely without risk. However, the magnitude of that risk is largely determined by the approach, not the material.
Frequently Asked Questions
How does inflammation typically manifest?
It may appear as swelling or pain in the injection area, or a lump may be felt when touched. The degree varies from person to person, so if you notice any unusual reactions, it is safer to check with the clinic where you received the procedure immediately.
I heard that hyaluronic acid fillers can be reversed.
It is true that there are dissolving agents available to address problems. However, that is a remedy after a problem has occurred, and the initial safety depends on where and in which layer it was injected.
Aren't collagen boosters safer?
The fact that a needle is used is the same. If the procedure is performed too close to blood vessels or if the layer is incorrect, there remains a possibility of nodules and inflammation. It is difficult to consider them safe simply because they do not "fill."
Should areas with many blood vessels, like the nose or lips, be avoided?
Rather than avoiding them, these areas require a more cautious approach. The location and depth of blood vessels vary from person to person, so a consultation process that first confirms the structure of that area is important.
What criteria should I use when choosing before a procedure?
In addition to the product name, checking whether the doctor explains the layers and thickness, whether they palpate blood vessels and muscles during the procedure, and what kind of post-care is provided can help with your decision.
Visit and Consultation Information
O.N Clinic is conveniently located near Gangnam Station, making it easy to reach by subway.
We can accurately discuss the blood vessel structure and appropriate layers for your areas of concern only after direct examination. For any questions, you can easily inquire via Chat for a consultation now.
Written by: Dr. Oh Seung-min (Chief Director, O.N Clinic; Graduated from Seoul National University College of Medicine; Academic Committee Chairman, Korean Society for Laser Dermatology and Hair). Detailed credentials can be found in Medical Staff Introduction. First published: 2026-09-01 / Last reviewed: 2026-09-02
This article is for general informational purposes only, and suitable treatments and results may vary depending on individual conditions.
