Blisters around mucous fistula?

Hey guys - I went to see my gastroenterologist again today. Three weeks post-surgery and everything is looking and feeling great (: except for one thing...

The past few days, the skin around my mucous fistula has felt particularly tender and sort of painful - when I stand up or sit down, it feels like a papercut being ripped open until my body adjusts to the new position. Yesterday when I was changing the dressing over my fistula I noticed that there was a small purple blister along the top edge. Now there are two blisters - one along the top edge and one along the bottom edge. They're bright red and painful and ooze a bit of clearish fluid when poked (I can't help but to investigate things like that on my own xD)

The gastro thinks it's just irritation from the bloody mucous that my fistula leaks.
Would it be wise for me to use Karaya powder on the blisters? :/ I use some of the powder around my ileostomy when I see a bit of red irritation there, but the fistula is different, so I don't know what to do to help it heal.

I wish I could! I'll have to call her office tomorrow to ask for her email address. I don't know why I didn't think of her earlier, either. xp Thank you.