Scar injection is a method of injecting drugs into the scarred body to make the scarred body atrophy and achieve the lightening of the scar. 1. The basic principle of scar injection is to inject medication into the scar, which will make the dermis of the scar thinner, reduce the synthesis of collagen fibers and increase the degradation of collagen fibers, which can effectively promote the shrinkage of the scar body, and achieve the effect of fading scars. 2. It should be noted that, if the scar is large, it is usually difficult to achieve the purpose of complete removal through the injection of scar injection, requiring multiple treatments, but also with the laser treatment method. After the scar injection daily life should pay attention to sunscreen, to avoid direct exposure to ultraviolet radiation scar parts of hyperpigmentation, but also to avoid scratching the scars with their hands. It is recommended that patients who want to have scar injections visit a regular medical institution and have the treatment done under the operation of a professional doctor.