The black marks left after the injury are caused by the increase of local skin melanin, which can be removed with the help of medication, medical treatment, strengthening of sun protection, and life conditioning. 1. Medication: For patients with light color and mild symptoms of black marks left after injury, they can apply hydroquinone cream, arbutin cream, azelaic acid cream, vitamin A cream, niacinamide and other creams to help accelerate the metabolism of melanin in the skin, thus helping to lighten and remove the black marks left by the skin after injury. 2. Medical aesthetic treatment: for patients with serious symptoms of black marks left after injury and greater impact on their appearance, they can try to remove the black marks left after injury through picosecond laser, Q-switched alexandrite laser, Q-switched ruby laser, chemical peeling and other medical aesthetic treatments, which have better results. 3. Strengthen sun protection: when patients are exposed to excessive ultraviolet radiation, it will make the color of the black marks left after injury deepen and become more obvious, so patients should pay attention to strengthening sun protection measures, you can use hats, masks, umbrellas, sunglasses, sunscreen, sunscreen spray and other sunscreen items, which helps to isolate ultraviolet radiation on the skin damage. 4. Life conditioning: In the above treatment process, patients should pay attention to strengthen life conditioning, help maintain good metabolic function of the skin, thus helping to leave the black marks in the melanin deposits better metabolism subside, such as patients should pay attention to a light diet; to ensure adequate sleep, avoid staying up all night; appropriate exercise and so on. Black marks after injury is recommended to follow the doctor’s instructions to deal with the above treatment and medication should be carried out under the guidance of a physician to avoid adverse reactions.