Bubble, Bubble, My Arm is in Trouble

I've been using the patch of poison ivy on my forearm as a teaching aid (the threat is that if you get the answer wrong, I will make you look at the rash up close, but no one has been subjected to this torture . . . I guess the method works) and it started kind of gross and bubbly, but now it has crossed the line into full suppuration—I put my arm down on a napkin, and I left a wet mark, which is beyond gross and into the repugnant neighborhood, and the pus is matting my arm hair as well, and I can't stop looking at it, and in some strange way, I'm going to miss it when it's gone.