Amber I know how hard it is to see, what looked like an okay to you (well other than the bloody poop) dog come home looking worse for wear. It's just the necessary evil of getting him well again. When Foxy had her breathing crisis last year she was perfect (except for the almost not breathing part) when she went in. She came home with bruising from the IV sites, a tube in her nose and it was glued to her head that bled when it was removed. She looked awful, but she healed and was so much better in the long run.
The hardest part is that he can't tell you how he really feels or what really happened so we imagine the worst. The worst didn't happen, and he is home with you. Trust them when they aren't worried, trust them more when they are. They will get to the bottom of this and it will become a bad memory.
Sending huge, but gentle hugs to you and to our SoulMan. :grouphug
Janet, Peanut, Jake and Jet