A friend in Utah has found this RES. I'm in WA now don't know anything about them. I've given her a list of reptile vets from the list here but what can she do for it in the meantime?!
It is minor shell discoloration and nothing to worry about. The top layer of keratin on those scutes will eventually peel off, showing pretty, new shell underneath. Set it up in water, the bigger the better, with a landing dock under a basking light. They need to be in water to swallow food.
You can buy turtle pellets from most stores, but for now he can eat cooked meat like chicken, pork and beef. They'll gobble cucumbers and carrots, small shrimp and even lunchmeat. If your not keeping him, then he'll be okay on just meat and no, like, special turtle diet pellets or anything.