A small black pimple on the testicular skin is mainly related to abnormalities in the skin tissues, and the causes of the corresponding conditions mainly include folliculitis, nevus pigmentosus and common warts. 1. Folliculitis: localized inflammatory reaction, hair follicle blockage, causing the accumulation of secretion with a small amount of bleeding, there will be corresponding symptoms. 2. Nevus pigmentosus: a benign lesion, mainly due to local pigment cell hyperplasia, repeated friction stimulation, may cause pain. 3. common warts: and viral infection is closely related to the normal and the surrounding soft tissue color, when the local blood circulation condition is abnormal, there may be a black change.