I've got a Black 08 Wolfsburg that has a big scratch all the at the bottom of the rear door panel, its actually low enough that if you feel the bottom of the car, its rough and textured. It almost feels like a silicone or rubbery like material down there. My question is, what should I use to fill this in? It's about a 8" scratch, but not very wide, maybe only 1/8" - 1/4" wide. I found this paint repair pen, but will it work on this different kind of finish?