Circumcision scab 21 days is not good, mainly considered with improper care, frequent erection, local infection and other factors. 1. improper care: in the recovery stage, the patient did not do a good job of nursing, or strenuous exercise, resulting in wound collapse, can appear scab 21 days did not recover the phenomenon. 2. Frequent erections: During the recovery period, frequent erections of the male penis will also affect the speed of recovery of the wound, resulting in the scab is still not recovered after 21 days. 3. Localized infection: the presence of germs in the affected area, and then the inflammatory reaction, will also affect the wound recovery. The reason for this situation is more complicated. It is recommended that the patient consult a doctor in a timely manner to clarify the cause of the disease, and under the guidance of the doctor to deal with.