Side effects from blemish laser treatment are not due to bad luck, but rather the result of using a tool unsuitable for your skin. The biggest fear that makes people hesitate to seek treatment is the worry that their face might look worse after making a big decision to undergo treatment. If we medically analyze this vague fear, the core issue is surprisingly simple: safe treatment begins with accurately identifying what kind of pigment is on your face.
Blemishes are not one word, but have six faces
Most patients simply call them blemishes, but in reality, they are a mixture of pigments with different characteristics.
- Melasma with blurry borders, like a fog
- Tiny freckles, like sesame seeds
- Lentigo with clear borders, like a coin
- Seborrheic keratosis that protrudes on the surface
- Nevus of Ota located in the deep layers of the skin
- Post-inflammatory hyperpigmentation, like acne marks
While it may seem complex, the tools doctors use to treat them are broadly divided into two categories.
What to break with a hammer and what to remove with a knife
The first tool is a laser that acts as a hammer. Pigments located deeply or with blurry borders, such as melasma, Nevus of Ota, or post-inflammatory hyperpigmentation, are difficult to remove in one go. Therefore, a method is used to break down the pigment into very fine particles and slowly discharge them from the body. Toning falls into this category.
The second tool is a laser used like a surgical knife. Lesions with clear borders, such as lentigo or seborrheic keratosis, do not disappear well by hammering. In such cases, the lesion must be precisely separated from the normal skin and removed entirely. If one insists on using only one type of equipment without knowing what is present, the results are likely to be unsatisfactory.
Side effects appear at two extremes
The commonly feared changes in blemish treatment are two types with opposite characteristics. One is post-inflammatory hyperpigmentation, where the treated area, instead of lightening, actually darkens. This is sometimes described as the skin being "turned over." The other is hypopigmentation, where, conversely, melanin decreases or disappears, leaving white spots in its place.
Three factors contribute to these changes:
- Choosing equipment unsuitable for the skin condition
- The patient's unique constitution, prone to hyperpigmentation or scarring
- The medical team's experience in anticipating and avoiding obstacles
If the skin is prone to hyperpigmentation or scarring, it is safer to avoid strong lasers. Experienced medical professionals know what obstacles lie ahead and can guide the treatment to the target area while avoiding them.
The best approach is to prevent them from occurring in the first place
If pigment changes have already occurred, a long-term recovery plan of more than 6 months is necessary. Therefore, the best method is to design the treatment to prevent them from occurring from the outset.
One should not be greedy and try to eliminate all melasma at once. Since melanin is the cause, the key is to adjust the intensity and frequency to avoid destroying melanocytes. When removing lentigo, blood vessels are constricted using cooling technology. When blood vessels constrict, the laser reaction is reduced, preventing inflammation, and less inflammation leads to less subsequent hyperpigmentation.
Why precise aiming is as important as cooling
Cooling is not the only factor. Precisely aiming and treating only the target is equally important. The automatic tracking system is a technology that, like a fighter jet's targeting scope, tracks only the pigment in real-time and fires the laser. Even with subtle facial movements during breathing, it precisely targets only the pigment, minimizing damage to surrounding healthy skin.
A study published in an international academic journal verified the effectiveness of this system in patients with stubborn lentigo who had not responded to conventional laser treatment. The content describes how it rapidly and effectively targets only the lesion, preventing skin damage, and treats evenly without missing any areas. The key point is that the reported good results were possible not just due to cooling, but also due to the addition of ultra-precise aiming technology.
The reason for insisting on expensive equipment and demanding technology is simple: a patient's face is not a practice canvas. We believe that safety, as much as effectiveness, is a principle that should not be compromised.
Results may vary by individual, and accurate diagnosis and treatment are determined after consultation.
Written by Dr. Sang-Joo Lee, Chief Director (Yonsei Star Dermatology) · Medical Staff Introduction · Last reviewed 2026-06-04