You have a gift for imagery. Night munchies aren't an issue for me now. Your use of watermelon as a descriptive device was quite powerful.
I mean, and if my logic is flawed I apologyze, but it just sounds like your snake didn't consume anything out of the ordinary. A thawed rat isn't going to bleed like a fresh one would. Frozen seem to wilt and "sweat" when thawed. I personally wouldn't worry.