Nevus is a developmental malformation of melanocytes, which is formed by local aggregation of melanocytes prompted by some incidental factors during the movement of melanocytes from neural crest to epidermis. Clinically, it can be manifested as a rash that does not protrude from the skin to a papule or nodule that is higher than the surface of the skin, and the sites of onset include the head, face, limbs and feet, and can occur in any dermatomucosal area, so the cause of onset is the same regardless of where the nevus grows, including the head. Generally, moles do not need deliberate treatment, but if the moles themselves are relatively large and are usually prone to repeated friction and irritation during hair washing and haircutting, or if the moles themselves continue to be painful, itchy, or even break out and ooze, surgical removal can be considered in such cases.