Keep him warm - hot water bottle, heat lamp, heat pack etc.
Mix some sugar and water with a little salt ( warm water ) and spoon feed it. That acts as electrolytes ( a wildlife rehabber told me that if you don't have any actual electrolyte on hand.
Stop any bleeding asap.
Keep a light on him at all times.
Look up vets in the phone book, if no vets then ring up a wildlife rehabber and ask for advice.
Then touch him and move him about as little as possible, he's probably in shock.
Good luck.