Sudden growth of moles on the face may be related to stimulation by external factors and abnormal hormone levels, but it is important to prevent the possibility of malignant changes. Long-term ultraviolet radiation, ionizing radiation, formaldehyde and other harmful substances exposure and other external environmental stimuli lead to melanin deposition, or even genetic mutation, may suddenly grow moles on the face. Changes in hormone levels can also lead to sudden growth of moles, such as during pregnancy. If one or several pigmented moles suddenly appear in a short period of time, and grow rapidly, with uneven color and unclear boundary, and accompanied by skin breakage, itching, bleeding, and pain, it is necessary to raise vigilance and exclude the possibility of malignant changes, such as melanoma. It is necessary to consult a doctor in time for clear diagnosis and treatment.