Once you've got a ding, you're pretty much stuck with it until the area can be repainted. Probably best to wait a couple of years and then get a paint job, I dunno. The trick is to not get the ding in the first place. I'm incredibly picky about where I park my car. If I'm parking at a mall or store, I always insist on parking on the end, and leave lots of space for the car next to me. I'll park far out as necessary, and walk a lot of extra distance. Same applies at work. I'm lucky we have a big parking area at work with lots of space.
Anyway, sorry to hear, I hate dings.