My horse did the exact same thing when her hooves were trimmed but they weren't overtrimmed. It was just because she needed shoes.
You could always tell your farrier what happened and he'll take less off next time. Tbs have a tendency to have poor hooves so I suspect he will need shoes, especailly if he's flat footed.
I doubt he'll be ok by tomorrow - its likely that it will take weeks. You can try him and see, but its very unlikely. I know its disappointing, but its what's best for your horse.