Redness and swelling of the urethral opening after circumcision can be caused by factors such as over-tightening of the bandage, surgical injury, and postoperative infection. 1. too tight bandage: after surgery, due to the presence of congestion and edema and other symptoms, the need for pressure bandage, bandage too long, resulting in poor blood circulation in the urethral region, there will be redness and swelling of the symptoms. 2. Surgical injury: improper operation of circumcision, resulting in localized damage to the glans, there will also be localized redness and swelling, which may also be accompanied by pain. 3. Post-operative infection: after the operation without good daily care, may lead to wound site infection, infection is serious, may invade the urethra, can lead to urethral urethral redness and swelling, accompanied by itching, tingling and other symptoms. Redness and swelling of the urethra after circumcision may also be caused by other factors, and it is recommended that the patient consult a doctor for examination and timely treatment after the causative factors are clarified.