The black marks left after being bitten by mosquitoes are usually caused by post-inflammatory hyperpigmentation, which can be eliminated by strengthening sun protection, medication and medical treatment. 1. Strengthen sunscreen: the black marks left by mosquito bites will be more obvious after being exposed to excessive ultraviolet radiation, so to effectively eliminate the black marks, patients should pay attention to strengthening sunscreen measures, such as going out can use hats, umbrellas, sunscreen clothing and other physical sunscreen products, you can also apply sunscreen and other sunscreen products, to help effectively insulate ultraviolet rays. 2. Medication: For patients with relatively mild symptoms and inconspicuous black marks left by mosquito bites, you can apply compound arbutin cream, hydroquinone cream, azelaic acid cream, retinoic acid cream and other creams locally to help lighten the local black marks, so as to achieve the effect of eliminating the black marks. 3. Medical aesthetic treatment: for patients whose black marks left behind by mosquito bites are more obvious and have a greater impact on their appearance, Q-switched ruby laser, Q-switched emerald green gemstone laser, picosecond laser, chemical peeling and other medical aesthetic treatments can be used to help lighten the black marks left behind, which has a better effect. The above treatments need to be carried out under the guidance of a physician, black marks left behind by mosquito bites should be promptly to the hospital to avoid self-medication.