I would mainly keep an eye on him and see how he does for a few days. Watch to see if he's eating and drinking. If he isn't, then you'll need to help him. I know you've started to give him water, already, which is really good. The easiest way to give him water would be to use an eye dropper, to offer him drops of water. If he's not eating, either, then you could add a little sugar to the water, just to keep him going. Just like when you're trying to revive new chicks that have had a hard trip.
The biggest problem people can have when giving water or liquified food to any creature, is to force a bunch in and have it either inhaled or run down into the lungs. That's pretty deadly. Just offer drops and let him swallow on his own and he should do well with it.
Although ACV can be helpful for a lot of things, I'd be concerned that it would sting and cause him more pain, with a fresh wound. I wouldn't want to make drinking painful or he might just avoid drinking. That would be my only worry with using it, while the wound is fresh enough that you saw a bit of blood.
After he gets through the first couple of days, he might appretiate having some of his regular food softened with water. Poor little guy. I hope he feels better, soon.
