Hi. Thanks for your query. Noted the history of taking Sulfa medicine for cyst, started with loose motions but at the end of completing the course have got impacted stools, painful to pass, can hardly sit down, wants to know what can be done to alleviate the horrible pain. You may please apply local Xylocaine ointment or jelly and take a painkiller that suits you. Secondly get a clinical evaluation and examination to see whether this is just an anal fissure or reaction to sulfa. If this is a anal fissure, take the following treatment: High fiber diet. Avoid all the foods and beverages and stress-like conditions which gives constipation. Laxative for softening the stool- never allow the dose too much to cause liquid stools. Sitz bath- very important- just before passing a stool and after passing a stool. Clean the area very clear of the fecal soiling that remains after cleaning; use cotton soaked in the same water to clean. You can apply liquid povidone iodine locally. Apply nothing else. 5 day course of an antibiotic on prescription of a local Doctor. Add probiotics and multivitamins. Avoid stress and mental tensions at any cost; this is a very important factor.