Small black mole is medically called pigmented nevus, nevus cell nevus, melanocytic nevus, which is the most common benign skin tumor. It is the most common benign skin tumor. It is normal for a one year old child to have a small nevus on his body. It is normal for small nevi to grow on the body, occurring in childhood or adolescence, and can occur in any part of the body, most common in the trunk, with black, dark brown, light brown spots or macules as the characteristics of the clinical manifestations. Generally speaking, nevi are unlikely to become malignant and most of them grow slowly and can last for many years without any change, so treatment is generally not necessary. However, parents should pay attention to whether the nevus continues to expand, and if it does, it is recommended to consult a doctor in time. If the nevus is just a simple pigmentation, there is no need to worry too much.