The blackening of the glans is not a normal change, if there is blackening of the glans, it is recommended to go to the hospital for further examination to clarify the specific causes. 1, if there is local blackening after circumcision or penile surgery, it is considered that local ischemia leads to blackening, usually with the further establishment of blood flow branches, the blackening can gradually improve, usually in 3-5 days after surgery, the blackening of the penis will be gradually relieved or disappear, only need to regularly If there is local blackening, accompanied by blackened surface higher than the skin surface, accompanied by local pain, etc., it is not excluded that black pigmented nevus or melanoma and other changes, it is recommended to go to the hospital for further examination, and if necessary, biopsy is needed to obtain a clear diagnosis, and then local blackened nevus excision surgery can be performed to completely remove the penile lesion. 3. If the rash is combined with bleeding, it can appear as blackening, especially if you take drugs that are easily allergic, a fixed drug rash can appear, and local blackening can also appear after combining with bleeding, so it is recommended to go to the hospital for further consultation, clear diagnosis and treatment.