Poor guy, I'm very sorry to see that. I hope that he recovers for you.
I don't know a thing about prep H for small amphibians, so I can't help you there, but I will say that Dr. Greek is probably your best bet for emergency herp care in Orange county.
http://gavh.net/articles If this happened to me, I think I'd just stick with the sugar solution until I can call first thing in the morning. Definitely keep him off his coco mulch until he's better.
Wishing him a full and speedy recovery!