Oh No! Another Fistula?

Distressed today.  DH had to go to walk-in clinic on Saturday am due to a fast growing "sore" on his abdomen.  It started out looking like a pimple, but quickly grew with a reddened hard area around it.  PA said it looked like cellulitis, gave him wide-spectrum antibiotic in case it was MRSA and told him to see PCP on Tuesday.  Saw doctor yesterday, she said she is afraid it is a fistula.  DH already has two closely spaced on upper adomen.  She did a culture and swabbed around at sore to try to open it so it would drain and said when finished that it should start draining a lot, but it has not.  It appears to be a lot better, reddened area and hardness around the sore has greatly diminished.  She will see him again tomorrow and said we might have to visit a surgeon.  DH's other two fistulas did not appear like this has, there was no opening/sore, just reddened fevered area.  The drainage has no foul odor so we are praying it is just a boil/cellulitis about anything other than another fistula!  He is not a candicate for surgery at this point and struggles so with the ostomy appliance on the current two fistulas.  Not sure he/we can deal with more.  Anyone had an abdominal fistula appear in this manner?

I'm not sure, I'm sorry. :( Good luck!

Here's hoping it's not a fistula, but a boil instead. It seems odd to say that but I know I fear another one showing up and I've been much more fortunate than others.