I think it was Emom (thanks!) that mentioned on here EarthClinic.com and I have been addicted to it ever since, reading alot of interesting alternatives. What they recommend is Apple cider vinegar for sinus infections among alot of other aliments. I just cured a nasty yeast infection with it (that's another story!!!!) The stuff is amazing. My son had a canker sore in his mouth and I made him swish some in his mouth before school and afterschool it didn't bother him anymore.
Anyways, read up on this its worth a shot. Some recommend using a netti pot and ACV solution, others drink about 2 tbsp in a glass of water and they say the results are good. Not too sure about you drinking the ACV but I did look up crohns disease on this site and some can tolerate the vinegar no problem, everyone is different as we know.
I just felt this was worth mentioning. I hope you feel some relief soon!