A hard lump on the left side of the penis after circumcision may be due to the presence of granulation tissue and scarring hyperplasia, and may also be due to the presence of inflammatory nodules. 1. Granulation tissue: After surgery, due to the presence of surgical incisions, the local area may be newborn granulation tissue, which may lead to local hard lumps, usually bright red, conducive to repair and fill the wound. 2. Keloid hyperplasia: In the process of wound healing after surgery, keloid hyperplasia may occur, which may cause a hard lump on the left side of the penis, and the lump may disappear on its own. 3. Inflammatory nodules: improper care after the operation, resulting in localized infection, aggravation of the infection will lead to localized inflammatory nodules, which may lead to localized hard lumps, accompanied by itching, pain, redness and other symptoms. If you have a hard lump on the left side of the penis after circumcision and there are other abnormal manifestations, it is recommended that you seek medical attention for examination and treatment.