I wondered how this thread would turn out after:

Since yesterday morning I have been cleaning the wounds and putting a triple antibiotic on them, and leaving the collar off. Since then he is getting better. His fever has gone away, he's eating like a pig again
Fever equals infection as in systemic infection, which would also explain the anorexia. Given the original wound was described as oozing, smelly as in probable Clostridia infection. Such infections are deep, and not readily treated by any surface antibiotic salve. Neither will a systemic infection be affected by treating the skin superficially. Might decrease the toxin load on the system, but necrotic tissue isn't going to respond well to antibiotic salve. The normal progression of such an infection in an older dog without antibiotic therapy would be septis, multiple organ failure and death.

Maybe an unexplained Christmas miracle.