Question for the hammer and dolly gods

[woodwright]

I'm working on the passenger door of my 70 chev.


It had a lite crease in it where the black line is. I've worked out most of the damage, but I still have a gradual indent in the door.

It's about 1/8" in the middle. The back side is really hard to get to, and there is a layer of undercoating(I think). I don't want to bondo this, but I can't figure out how to finish it. Any help would be great.