Suggest Remedy For Anal Fissure Due To Hard Stool

My 13 year old has hard stool trapped in her rectum. She has IBS and because of a previous issue with this she has what I believe an anal fissure because part of the problem is that it s very painful to push to help evacuate the blockage. What should I do? At this point she is fighting going to a doctor because it s only been 3 days but it s going to get worse if she can t pass it soon.