Box Turle injury!

I pulled a box turtle off the road last night- his shell was intact, and he is active and alert, however, this morning I saw that he was bleeding rectally. I have hime confined in an enclosed pen in my garden with sun, shade, and grass underneath. I placed a shallow pan of water in it- that is where he is right now. He showed some interest in swiss chard greens. I do not have a vet anywhere close to taake him to... what can I do to increase his chance of recovery? Would it be good to offer red hamburger?