Fix bumper dent with hot water

I once had something like that happen to me back in the 80s. In the extreme cold I slid into a ditch on the way to work and put a crease in the door. Over the course of the day it got warmer and it popped out on it's own. Thankfully I didn't have to tell my Dad I dented his car.

If I had to have at a guess, I would say the extreme heat damages the paint

Amazing