I've been fortunate thus far and honestly haven't had many problems so I'm not really experienced in solving them. I do have some suggestions for you....this is what I'd do in your situation.
I will be guessing at what you are doing with the enclosure since you have only posted limited details. I would lower the temps by 5 degrees on both sides if possible. If you have a daytime light as your heat source I would change it to a nocturnal bulb (red or purple)or better yet use an undertank heater of the warm 1/3 of the tank. Assuming you are using a 10 gallon tank, I find it difficult to beleive that you are able to get an accurate temp reading even with a temp gun because to hold high enough humidity almost the entire top (minus the bulb reflector) must be covered. As soon as the top is removed massive amounts of heat will escape and at 82 immediately upon cover removal, it must be much hotter in there than you might think. The humidity should be no less than 90% always.
I would use a plastic container of some sort no bigger than a shoebox size and soak the snake by using 78 to 80 degree water (temp gun the water) and fill the container 1/3 full for 20 to 30 minutes then replace the water with moist paper towels and a large enough bowl of water for the snake to coil in. Don't try to feed again for 24 to 48 hours and place that plastic container back in the bigger enclosure with it's reduced temps and leave it alone until feeding again an hour after dark (live fuzzy mouse) leaving the mouse in all night. A word of caution....if your temps are too high the inner container could get even hotter, so be very careful about watching those temps.
If that doesn't help, I would repeat the same steps in 2 more day. Be sure to handle the snake as little as possible until it begins to eat well and regularly.
Hope something in this will be useful for your PRB.
Linda
Oh NO!! I just reread that whole thing and see that your are using a digital thermometer instead of a temp gun. What was I thinking?? Oh well, I'm gonna post it anyway....maybe there's something useful somewhere. I don't have time to edit it now anyway.