Sep 28, - About three days ago I noticed a stationary lump slightly smaller than a jelly bean midway between my scrotum and anus; just left of center. A perineal abscess is an infection that causes a painful lump in the perineum. The perineum is the area between the scrotum and the anus in a man. In a woman, it's the area between the vulva and the anus. Your doctor may have done minor surgery to open and drain the abscess.