Mosquito bites on the legs left behind is not a scar but inflammatory hyperpigmentation, most of which can fade and disappear on their own, or you can apply topical ointment to promote its fading. Mosquito bites the human body will leave behind foreign substances will cause the body’s immune response, resulting in local inflammation, the inflammatory response to stimulate the skin local melanocytes to produce melanin, and melanin transfer to keratinocytes, while macrophages phagocytosis of melanin and migrate to the dermis, then the formation of the black marks that we see. Without any intervention, the dark marks will gradually fade away after half a year. If you want to shorten the recovery time, you can use topical ointment mainly hydroquinone cream, retinoic acid, azelaic acid, etc., and the general course of treatment is three months. It is recommended that patients go to the hospital when necessary, follow the doctor’s instructions for standardized treatment, do not self-medication.