probably old enough to be on its own, then its most likey eating on its own .
Until you can find a rehabber, I would first clean the wound, apply neosporin or some antibiotic ointment to it, even vasoline if you don't have ointment.
Then I would put him in a secure area , quiet, so he can calm down from his ordeal. Maybe put a box in the cage with him with a small hole he can run in, and feel as though he can hide. Have water available in a shallow dish.
I would just pull grass, dandilion greens, and clovers, (exactly what he would be eating out side himself) make sure its not treated with any harmful chemicals.
And then leave him rest. Some times cats bite down very hard and leave internal damage also, that you can not see.
So just hope for the best. let us know how he does.
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