The black marks left by mosquito bags generally refer to hyperpigmentation, which can be removed with topical medications and physical therapy. 1. Topical medication: Topical medication is suitable for patients with mild symptoms, and commonly used medication includes hydroquinone cream, which can inhibit the metabolic process of melanocytes and has a good therapeutic effect on post-inflammatory hyperpigmentation. Since hydroquinone is a photosensitive substance, it is recommended to apply it at night. During the process of use, the skin at the site of application may experience redness, irritation, itching and other adverse reactions, and it is recommended to use it under the guidance of a doctor. 2. Physical therapy: physical therapy such as photorejuvenation, photorejuvenation uses specific wavelengths and energy to act directly on melanin, breaking it down and crushing it, so as to achieve the purpose of removing hyperpigmentation, but contraindicated for pregnant women, light allergy, hypertension, diabetes and other people. Mosquito bag left the black mark is mainly due to hyperpigmentation caused by mild symptoms will mostly subside on their own, you can eat more food rich in vitamin C, such as cabbage, oranges, etc., at the same time, pay attention to sunscreen, sun exposure is prone to aggravate the hyperpigmentation, so that the black mark is more pronounced. Patients who have the need to remove hyperpigmentation are advised to go to the dermatology department of a regular hospital, and after clarifying the cause of the disease, treat the symptoms under the guidance of the doctor, and do not use medication on their own.