Hello and thank you for your question. I can understand your concern and rectal fissures can definitely be painful. If you have a family history of Crohn's disease, fistulae can occur and if there is any reason for concern and/or for routine screening purposes, you should be seen by a gastroenterologist for a colonoscopy. This will help to determine whether there is evidence of inflammation and whether this may be contiguous with internal structures.
I hope you feel better and please let me know if you have more questions.