He's fine, that temperature isn't too much. And you can generally trust the temp gun.

I have female snakes that push their aspen out of the way and nest right on top of the heat tape in their tubs. And both the males and females will hide under their paper if I use that instead. I've started folding the newsprint so they have a snug little fold they can crawl into. But sometimes all they really want is to just sit on the warm spot. They're like cats sleeping on computer monitors.