Fractional is what is clinically referred to as a fractional laser, and the skin will be reddened after it is done. The principle of action of fractional laser is to pass the laser through the surface of the skin, producing a tiny treatment area that stimulates the proliferation of its own dermal collagen fibers, thus improving the skin texture and complexion. Redness of the skin after fractional laser treatment is a normal phenomenon. The skin is divided into epidermis, dermis and fat layer. When the laser penetrates the epidermis of the skin, it will cause certain damage to the cells of the stratum corneum as well as the hair layer, which will result in redness, and when it reaches the dermis, it will stimulate the proliferation and reconstruction of collagen in the dermal tissues, so that the skin will redden after the fractional laser treatment. After fractional laser, the redness and burning sensation of the skin will last about 2 days, and the scabs will start to form 1-2 days after the treatment, and will return to normal in about 7 days. In order to prevent infection, swimming, showering, sauna and sun exposure are prohibited until the scabs fall off after the treatment. The recovery period after treatment is about 2-4 weeks, during which you need to strictly protect yourself from the sun to avoid hyperpigmentation. Nowadays, the latest non-peeling fractional laser can effectively avoid the occurrence of the above situations, and can be chosen to use under the guidance of doctors.