neondream :)
Please check out this link, it shows both kinds of hemmies (first set of pics) but it also shows pics (second set of pics under pics of hemmies) of perianal crohn's skin tags (aka: elephant ears) which are directly related to crohn's disease only...if that's what your butt looks like then I'd be going to the doc and having him check (which you should do regardless) because it's not uncommon for people to be misDX with UC when they infact have CD.
http://www.emedmag.com/html/pre/fea/features/011504.asp
:)