There is a great possibility that this condition is infected by parasites in the stomach. You can go to the hospital to do colonoscopy or parasite-related aspects of the examination, such as looking for eggs in the stool or looking for worms in the intestines, etc., and look for an anorectal doctor or infectious disease physician to visualize and palpate the anus in order to make a clear diagnosis. If there has been a delay, the worms will ovulate and then produce new worms, which can seriously bite the anal wall and perforate the intestines, or block the intestines leading to intestinal obstruction and necrosis. Once the diagnosis of parasitic infection is confirmed, early intervention is needed. It is recommended to clean the anus and the surrounding tissues from time to time, change the underwear frequently, and disinfect the underwear after changing, and take oral deworming medication accordingly, commonly used medications include intestinal worms.