Suggest Medication For A Large Cyst In The Groin

my 83 year old father had a bladder infection in December 2010 with severe upset stomach . the doctor called to the house and gave antibiotics. he was in bed with high temp and incontinence for about 4 days.since then he has had his antibiotics changed twice. he has now developed a large cyst in his groin which is bleeding. the Doctor is sending him for some tests at the hospital in 4 days time. what do you think is the problem