Well, i've got her home now, in a temporary tub (on newspaper with a hide in there) while I clean out her tank.
The doc said it did seem to be an infection, but wasn't very clear, and didn't seem totally certain.
Then again, I was pretty certain that it wasn't a burn because I keep a good monitor on the temperatures.

I came home with a tub of "Malaseb Pledgets" from the vet, which are Rayon/Polyester tabs with Miconazole (17.4mg) and Chlorhexidine Cluconate (20mg) and Alcohol.
The vet recommended that I clean her underbody with the tabs; as I was doing so, I noted that the skin did look more burned than infected at some points. The doc recommended I use Neosporin to treat the area, which my Dad (who doesn't like snakes) applied as I held her belly-up. She was surprisingly very calm, and kind of just watched as he did it, even though her body would squirm slightly at the touch and she was obviously uncomfortable. She didn't try to wrestle her way free though

I also cleaned out the tank, and as I was doing so, I realized that underneath the substrate, directly over the UTH, the temperature was definitely hot to the touch! I put my thermometer sensor directly on that spot, and wouldn't you know, the temp shortly rose above 120°F!
I'm thinking this is a burn now, and I will check back with the vet when I can. It was an expensive trip though, but I've definitely built a bond with Irie that I don't want to lose.