At the early stage of melanoma, patients may have symptoms such as nevus becoming asymmetrical in shape, hardening in texture, enlarging in diameter, itching and pain. 1. Asymmetrical shape, hard texture and large diameter: under normal circumstances, nevus is symmetrical in shape, even in texture and small in diameter, but if it develops into melanoma, it will have obvious changes in shape, which often manifests itself as asymmetrical and large in diameter. 2. Itching and pain: under normal circumstances, nevus of melanoma will not show any symptoms, but if it develops into melanoma, there may be sudden and continuous itching, swelling, pain and other symptoms, and then patients should pay attention to it. Most melanoma develops from nevus, therefore, you can’t squeeze or scratch the nevus in daily life, and if the nevus is abnormal, you need to consult a doctor in time.