Acne is a chronic inflammatory skin disease of the sebaceous units of the hair follicles. It mainly occurs in adolescents and has a great psychological and social impact on them, but it can often be naturally reduced or cured after puberty. The clinical manifestations are characterized by polymorphic lesions such as acne, papules, pustules, and nodules on the face. The occurrence of these lesions is mainly related to excessive sebum secretion, blockage of sebaceous ducts, bacterial infection and inflammatory reaction. After puberty, the level of androgens, especially testosterone, increases rapidly, which promotes the development of sebaceous glands and the production of large amounts of sebum. At the same time, abnormal keratinization of the hair follicle sebaceous gland ducts causes duct blockage, resulting in obstruction of sebum drainage and formation of keratin plugs or microcomedones. A variety of microorganisms, especially Propionibacterium acnes, proliferate in the hair follicles. The lipase produced by Propionibacterium acnes breaks down sebum to produce free fatty acids, which also chemotactic inflammatory cells and mediators, eventually inducing and aggravating inflammatory reactions. Current treatment for acne: whiteheads and blackheads: fruit acids, VC, fire acupuncture, herbal mask treatment; papules, pustules, etc.: treatment with red and blue light. What is red and blue light? Red and blue light treatment instrument uses high-purity, high-power density red, blue and yellow light to irradiate the skin, which can change the cell structure, kill bacteria, provide a suitable environment for new cells, enhance the production of new collagen elastin and collagen, and promote cell growth; it can repair inflammatory acne aging skin, relieve sunburned skin without harming the skin, whiten the skin and promote skin elasticity. Twice a week, 8 times a course of treatment. From the current efficacy, blue light sterilization with red light repair acne treatment is effective. Severe acne patients can be combined with photodynamic therapy, photosensitizer selection Ira, after applying the photosensitizer, avoiding light for 2 hours, red and blue light irradiation, once a month, three times for a course of treatment. The treatment effect is remarkable, but it should be especially noted here that Ira is a photosensitizer, so you should avoid light for 48 hours after doing it, and your skin will gradually darken, but this is only a temporary darkening, after 2 months, you will see a different you.