Acne marks after acne are usually caused by melanin deposition after inflammation, and patients can prevent acne marks through topical care, topical medication, and physical therapy. Acne marks are inflammatory hyperpigmentation that remains after acne heals, and are mostly yellowish-brown or dark brown in color. The main ways to prevent inflammatory pigmentation are to control local infection and promote acne healing. 1. Local care: avoid scratching or squeezing the infected area in daily life to prevent the infection from expanding and causing hyperpigmentation and scarring. 2. Topical medication: Antibiotic ointment can be used under the guidance of specialists to fight infection, such as fusidic acid ointment, mupirocin ointment and so on. 3. Physical therapy: Acne is usually caused by Propionibacterium acnes infection, so photodynamic therapy with red and blue light can be used to destroy Propionibacterium acnes and reduce the inflammatory reaction. In order to avoid leaving acne marks after acne, it is recommended that patients go to regular hospitals for timely examination and standardized treatment under the guidance of specialists.