Danny B. has a Youtube channel that is mainly about cars and video games.
Since he owns the lovely red Saab 9-3 Sport Sedan, he often puts on its channel videos on the theme of Saab cars. Most recent video is dedicated to DIY repairs of a big dent in the bumper. This was Very hard dent and deep in multiple areas.

Because car dents are one of the most common repairs, it’s worth learning how to fix a small dent at home so that you don’t have to take a trip to the mechanic. Plastic bumper dents are blemishes to otherwise seemingly perfect-looking cars. You could replace the entire bumper, or you can try one of these quick and easy fixes from home.
Useful Trick To Fix A Dented Saab Bumper At Home Using Only A Hair Dryer (or a Heat Gun):
If a dent is a small, the effects of such repairs will be much better, and there will be no need to re-painting car. It will still need some polishing, but your car will be back as good as new.