Chances are, seeing it's not that deformed, the mouth that is, he would be fine. Does he seem to have problems eating? If not, I would put him back where you found him. Maybe he will just hang around there to live. However, be careful then of using a weed whacked or lawn mower.
I wanted to put him back but my Grama isn't having it. She will "relocate" him if he's in the garden again. She said she had already done this to a few big ones this summer so I better take him w me and at least if i relocate him I know it's a safe place. No weed eaters or mowers at least. No dogs or cars either.