Sudden growth of a black mole may be caused by pigmented nevus, seborrheic keratosis, chloasma and other factors, it is recommended that the patient under the guidance of a doctor to clarify the specific cause of the disease and then through medication or electro-optical treatment, etc. to improve. 1. Pigmented nevus: pigmented nevus is usually caused by benign proliferation of melanocytes. Patients can be treated by surgical excision or electrocautery. 2. Seborrheic keratosis: Seborrheic keratosis is usually caused by excessive proliferation of epidermal cells due to heredity, aging, sun exposure, inflammation and other factors. Patients can be treated by surgery, laser and electrocautery. 3. Melasma: Melasma is usually related to sun exposure, sex hormone level, heredity and other factors. Patients can use hydroquinone cream or azelaic acid cream externally for improvement. It can also be taken orally with vitamin C and vitamin E. If the patient suddenly grows a mole, it is recommended to go to the regular hospital in time and under the guidance of professional doctors for standardized treatment.