Just got back from the vet. Benny has a tongue ulcer on the end of his tongue. Thankfully, he did not have any growths or problem/broken teeth. My only frustration is how this could happen. He was not exposed to poison or hot items, and outside of chewing an electric cord (which he's never done before), the vet could not say.
He received an injection of antibiotic and one of an anti-inflammatory (non steroid). He ate a small amount of canned food when we got home (he hadn't eaten this morning), and I'll give him more canned tonight.
He was a very good patient, as usual.