Melanoma is actually an abnormal metabolism of melanocytes, normal human hair is black, our skin is colored, these melanocytes are present in every normal person, it is actually a protective role, only the presence of melanocytes under the skin can protect us from sunburn, the ultraviolet rays in the sun are harmful to the human body, so it is very necessary to have normal melanocytes The normal melanocytes are very necessary. However, there are some melanocytes, which are caused by some genetic mutation or external factors, and after malignant transformation, they become melanoma, but when they are not malignant, they have an abnormal metabolism and accumulation, so that some black nevi are formed. In fact, improper treatment may cause malignant changes of these moles. Therefore, we emphasize that if we suspect that we have moles, especially newly grown ones, if they are born with us, less than 0.5mm, we actually do not pay much attention to them, and if they do not grow fast; if they are larger than 0.5mm, or if they grow up in the past few years, but grow fast, we should let the doctor take a look at them and find a doctor to identify whether they have any risk of malignant transformation.