Turns out Hero didn't have either one of the two things the vet said he may have had. Basically, he was never going to lose a toe. THANKS FOR HELPING ME SLEEP AT NIGHT DR. DOOLITTLE.
Anyway, he's on some antibiotics that will hopefully make him a cheery widdle pushkin, and I bought some Epsom salts to soak his foot in. I haven't tried the foot-soak yet, as I'm sure it will end in tears for all parties involved.
But at least Hero is going to live to see his Bark Mitzvah! PRAISE ALLAH!