A mole mainly refers to a pigmented mole. If a mole appears painful, you need to carefully observe the appearance of a pigmented mole because the surface of a pigmented mole is stimulated by the outside world without any obvious factors, triggered by surface rupture, erosion, exudation, and enlargement. Because the nevus cells of pigmented nevus are stimulated by the outside world, the number of nevus cells is increased and the volume is enlarged and the nevus cell degeneration is triggered, depending on the situation, the benign pigmented nevus can gradually turn into malignant melanoma. It is recommended that if a pigmented nevus is painful and has obvious surface changes, you can choose to go to a local hospital for surgical removal and pathological examination. Histological changes can be observed through microscope and once it is determined to be malignant changes, it is recommended that it can be enlarged and the whole body lymph nodes can be examined.