A mole that suddenly grows on the right hand may be a nevus cellular nevus, sebaceous nevus or spider nevus, each of which has a different reason for its formation, and it is recommended that the patient be treated according to the cause of the disease under the guidance of a doctor. 1. Mole cell nevus: it is the pigmented nevus in daily life, and its formation is usually related to ultraviolet radiation exposure, heredity or trauma, which causes melanocyte aggregation and occurs. 2. Sebaceous nevus: Sebaceous nevus is caused by the abnormal proliferation of sebaceous glands, which can involve epidermis, dermis and other tissues, and is a kind of benign misshapen tumor. It is currently believed that nevus of sebaceous gland is associated with abnormal development of epidermis, dermis and skin appendages. 3. Spider nevus: Spider nevus is usually formed due to the dilatation of the ends of small arteries in the skin. It can be formed in adolescent women with high estrogen secretion. It can also be formed in patients with cirrhosis of the liver or liver cancer. For the right hand suddenly grows a mole may also be other reasons, it is recommended to go to the regular hospital in time for examination, under the guidance of professional doctors for standardized diagnosis and treatment.