The roof of his mouth is apparently sporting a pair of identical ulcers, which indicate that he swallowed something Not Good For Him. The only thing I own that could cause that kind of damage is Soft Scrub--I tore the house apart looking for dangerous chemicals, and that's the only thing remotely menacing I found--so hell if I know. So I am wallowing in neurotic guilt, as one might expect.* (My paints are actually incredibly innocuous, being acrylic and watercolor, I use no thinners, I have no hair relaxers, the aquarium de-chlorinator was single dose, and to make matters worse, he developed the problem while I was out of town, so there were probably no witnesses to the act.)
Still, in the grand scheme of things, this is actually not that bad compared to what it COULD have been (cancer, abscessing on the roof of the mouth, etc) and while they're running bloodwork to make sure that if it WAS a chemical, he isn't suffering from any bad side-effects (kidney damage being the great concern) it'll hopefully respond to a round of Clavamox and painkillers.
My poor beastie.
Ursula, running through available chemicals in her head and grasping at straws: "Um....this couldn't have been caused by lube, could it?"
Vet: "Do you know how much lube we use around this place? No."