From history it seems that you might be having chronic gastro-intestinal infection giving rise this problem.
Go for one course of ofloxacilin, tinidazole
combination for 3-5 days.
Due to constant irritation due to bowels there might be having soreness on the part.
Apply antibiotic cream locally.
Take light diet like curd, rice, buttermilk.
Take plenty of water.
Ok and take care.