That looks like acutal hunks of paint are missing. It would take a ton of filling and wetsanding, and even then your probably still going to go through on the high spots of the gouge in the plastic.
Not much you can do, probably. You can try a repair, but it will be far from perfect. It's under the bumper, so I wouldn't spaz over it that much. It ain't a show car, and I doubt most people will crawl under there to examine it.