Herndog, I had my first ileostomy done in 2010 largely because of an abscess - the surgeon went in to do a resection but because everything was in such a bad way he instead just cut out a small bit of bowel then gave me the ileo to allow that to heal and rest the bowel. I had that for a year and was relatively well for that year but did have times when I felt like the abscess was returning - I'd just increase my pred until the pain disappeared but I would not recommend this. After being rejoined and having more bowel removed I was ok for awhile then the abscess returned (plus others). I was in and out of hospital for months at a time until I had another resection and ileo 0n Nov 23 last year. This time the surgeon also removed an area outside of my intestine where the main abscess kept reforming - sorry I'm not clear exactly what, and also cut away numerous adhesions of the bowel to the back of my stomach cavity. Post surgery it was discovered that I'd developed a "collection" which I understand means uninfected abscess, under my liver which is about 9cm x 6cm (4"x2"). Its not giving me any pain or fevers so they are hoping it will be reabsorbed. I recently had an ultrasound and it had only grown so I haven't got high hopes of reabsorption.
Anyway, the point of this long story is that is highly possible your abscess has returned, or it could be a new one caused by the surgery. You should definitely contact your doctor or surgeon and let them know what is happening particularly if you are having pain or fevers. I can't believe how little time they had you in hospital. Was it keyhole surgery or are you super tough?
Let me know how you get on, intestinal abscesses are such a nuisance and seem to be very hard to get rid of in my experience. I really hope your pain is not the abscess and if it is that they can drain it and give you a course of oral antibiotics rather than having to return to hospital. :goodluck: