First off, don't worry about the meat; it'll be fine. Plenty cool enough.

Liver shots need WAY more than an hour... I'd give them closer to 4-6, because you never know which extreme you'll end up with them: they can be extremely lethal very quickly, or take up to six hours or longer... sometimes much longer. I wish you hadn't went after him at all tonight after describing what you did, but what's done is done. I'm glad you're back and waiting 'til light.

He could VERY easily jump the fence on such a hit. The good thing about it is it sounds like you've really got two directions to focus on... Search out the most plausible one in your mind tomorrow morning, and then go back to the other. If I were you, I'd spend the majority of the time searching for a blood trail to follow in the sunlight, then search one area pretty well and if needed, go search the other one with a fine-tooth comb. If you STILL haven't found him by then, then it's time to go back to the first one and leave unturned there either.