Update from this morning: I let it be overnight. While the foot still looks very bad, the rest of the kit looks a little better. It has a full tummy, a thin coat of fur, and is very vigorous in trying to squirm away (which is normal for kits, but in this case I'm sure is also from the pain)...
For some context - One of our doe just had her first litter sometime in the last few days. She didn't make a great nest to the point I didn't realize she had kits in it until today - some thin, loosely arranged hay and a small spread of fluff in the box, with a large amount of fluff still strewn...