Crohn's/Fistulas.

I just had surgery on the 5th of this month for Anal Fistulas. The problem was so bad they could only put a Seton in place. I have not been bleeding much, until after I went to my doctors on the 11th. She packed the wound with A LOT of force, I was screaming with pain.. and now the wound bleeds and bleeds. Is this normal or did she mess something up? And also, can you really diagnose Crohn's with a biopsy? I thought it was a disease you could just look at the colon and be able to tell. How would a biopsy give you the answer? And what else could cause the fistulas and a 'suspicious' looking colon besides Crohn's? The biopsy results came back normal, but the Fistulas were so horrible, and the doctor only got 6 inches in my colon and said it was very suspicious looking..