Mag,
I developed a fistula this past March and it came out thru my old hysterectomy scar of all places. My gi immediately put me back on Remicade and a round of Flagyl. The Remicade took care of it and it closed up nicely and I have not had any more problems. We did not pack it either, just let it drain. It did not take all the long for the Remicade to kick in either.
I would highly suggest you get yourself another gi. The idiot you are with now seems more worried about him, instead of you, his patient. You do not leave a fistula untreated.
I hope you will get to a much better dr.
Susie