Fitting a custom mesh grille

[AlexNet0]

here is my problem, im posting pics of my damage, gotta figure out a way to get that dent out of the rear panel, the bumper was an easy fix, just order another super duper specialicious one. lol

If anyone knows if I can reach that panel from the inside to bang it out, that would be awesome, just want to ask before I rip out the interior trying.

Edit: And yes I know my rears are bald.