<s>[INST] I have this huge bump near my anus it bursted quite a bit and it was filled with blood and puss , it feels really hard right now and feels like there still is a lot in there.I have known people to get them on there inner thighs but not here. I dont know what this bump could be or how to treat it. Can u help me out? [/INST] HiT hanks for seeking our advice. I appreciate your concern for the painful pus filled blister at the anus. I am of the opinion that you have a perianal abscess which could have been caused by a fistula (an abnormal connection between the anal canal and the skin). When this fistula gets blocked it results in infection causing pus filled blisters which get burst releasing blood and puss. Get examined by a surgeon for proper examination and a possible histogram to know the extent of the abnormal opening so that it can be removed surgically to prevent recurrent infection., Hope this suggestion could be useful in getting the treatment. A feedback is appreciated. </s>