The nail mother nevus is on the nail mother or nail bed covered by the nail. Treatment of nail mother nevus requires opening the nail covered by the surface, fully exposing the nevus, removing the nail mother and the lesions on the nail bed completely and then suturing them together. The recurrence rate of nail mother nevus after surgery is low, but the naked eye observes that the lesions are limited and the scattered pigmented nevus cells cannot be seen, resulting in a small part of nail mother nevus not being completely removed, and there are black spots on the new nail and the black spots keep growing wider, which can be considered to be treated by surgery again; nail mother nevus involves all nails, and doing complete removal means removing the whole nail mother and no nail will grow again.