Moles can become bigger due to self-growth, local irritation and malignant changes. 1. Self-growth: Usually, moles will stabilize when they reach a certain size, but small moles that have just grown will gradually grow. 2. Localized stimulation: Moles may be stimulated to grow after repeated friction and other stimuli. Especially moles growing on the soles of the feet and palms of the hands are more prone to friction stimulation, which will show the phenomenon of gradual growth of moles. 3. Malignant transformation: Mole is a benign tumor, sudden growth accompanied by uneven changes in the color of the mole, or even ulceration, should be alert to the possibility of malignant transformation. When the phenomenon of nevus getting bigger, patients are advised to go to the hospital in time and exclude the possibility of malignant transformation.