Scratched bumper

[Trinity]

Some idiot backed into the rear side bumper at work today. Plenty of their tail light on the ground below my bumper. And of course, they didn't leave a note.

The only damage to the H3 is a small scratch on the black metal bumper near the license plate (which I've just about rubbed out and covered with a black Sharpie). However, the black plastic piece with the little groves has a bit of a mark on it. I tried to rub it out, but it still looks kind of white.

Any suggestions on how to get it out? Maybe slightly heat it with a hair dryer? I know that the Avalance owners used to get scratches out of their cladding that way.

Thanks,
Trinity