Not a good idea. First, PDR doesn't really work well on plastic - when the car got hit the plastic distorted a lot more than you're seeing now and the paint and primer are now damaged and probably separated from the plastic of the bumper. Trying to pop them out with PDR can cause the paint to flake immediately.

The reason you replace the whole bumper is that its easier than sanding off the damaged one and repainting. Now that the bumper has been deformed, the paint can start to flake off over time - this is why even minor fender benders routinely cause $2000 repair bills - the parts have to be replaced.

Best bet is to go through insurance and just get a new bumper.