The cause of nevus on the face (medically known as nevus, nevus cell nevus) is unknown at present, the pathogenesis is that melanocytes in the process of moving from the neural crest to the epidermis, due to accidental anomalies caused by the local aggregation of melanocytes, which may be related to genetic factors, environmental factors, neuropsychiatric factors and so on. 1. Genetic factors: nevus cell nevus is related to congenital heredity, and due to genetic predisposition, nevus cell nevus will grow on the skin. 2. Environmental factors: If you do not pay attention to sun protection, resulting in ultraviolet rays directly irradiate the skin, or subjected to ultraviolet radiation, then it is easy to lead to the active proliferation of melanocytes, nevus cell nevus appears on the skin. 3. Neuropsychiatric factors: If long-term stress, nervousness, depression, etc., will easily lead to a decline in the body’s immunity, metabolism slows down, endocrine disorders, which will easily lead to hormone level disorders, which will promote the production of melanin and the emergence of nevus cell nevus. It is recommended that patients usually pay attention to good sun protection, keep a relaxed mood, if the mole cells grow in the parts of the skin that are easily subject to friction, such as the groin, armpits, palms, etc., it is best to go to a regular hospital in a timely manner for treatment.