80 degrees is not hot enough for him. He needs to get his body temp up to 92-92 in order to digest properly and efficiently. I would seriously suggest raising the temperatures on one end of his cage.
It sounds like he hasn't adjusted to being home yet. I would leave him entirely alone for another week before offering prey. I am afraid that you're overwhelming him. Getting him to feel comfortable is more important than getting food in him right now. Remember, he was probably man handled at the vets to kill the mites. He would have been taken out of his enclosure several times, back and forth, so that they could treat it. Let him just sit and relax for a little while before you offer food again.We have only had him for 3.5 weeks and of that he spent 2 weeks at the vet being treated for mites.