Whether laser treatment will leave scars depends on the type of laser used and the kind of treatment performed. Most cosmetic lasers generally do not leave scars, such as photorejuvenation, hair removal, etc. Laser treatments do not leave scars, and some pigmentation treatments, including nevus of Ota, freckles, melasma, coffee spots, and post-inflammatory hyperpigmentation, also do not leave scars. There are also some laser treatments for reddening, including some vascular diseases, such as nevus, capillary dilation and some of the hemangiomas, etc. These skin problems are often treated by laser without scar formation. However, there are some skin diseases that may require laser grinding or peeling, or may require laser action on deeper layers of the skin, such as seborrheic keratosis and spider nevus, and the depth of the lesions of such diseases is usually deeper, and there may be scar formation after laser treatment, so most laser treatments will not leave scars, but if the lesions are deeper and destroy the basal layer of the skin, there may be If the lesions are deeper and damage the basal layer of the skin, scars may appear.