Can anyone just tell me if I'm on the right track here?

The ambient temp in his tub is usually between 75-80 degrees, and the heat pad itself (as told by the temp probe) is reading in at 108 degrees right now.

I have the heat pad taped onto to the bottom of the tub. Should I just let it rest under the tub instead of be tapped to it? Will that help whatsoever?

At what temperature is the heat pad unsafe? I'm keeping the area of the heat pad covered by lots of paper towel right now to keep him from getting burned (as I imagine 108 degrees directly could be harmful) and hopefully I will be able to get a thermostat ASAP (I looked all over town for what I needed and found nothing...)

Ugh I am so frustrated by this. Why don't the pads just stay the safe temp if they're built for snakes?