Heads up,...this exact same thing happened to me, a few months ago.
Minimal damage done, but still a hit. Actually this car has a great rear bumper design. In my case, the guy's front licence plate cover actually did the damage. It made a tiny scratch on the bumper skin, and made a small square puncture at the black plastic section just above the diffuser. In reality, its such minor damage I just shrugged it off.
HOWEVER, I was quoted 1009.10 to replace/repair, AND granted $750 per person in personal bodily damages, which is standard fare.
The reason you should still ask for a small sum of money for injury (even very very minor) is that things will likely surface months from now, and may need tending to. Small things like deep tissue massage and some small doctor's visits here and there.
Without giving legal advice, I can give personal advice. My personal advice is to approach bodily injury like this:
To insurance person you are in contact with:
"So, what do we do with the personal injury side of this incident? I'm not broken or bleeding or anything, but it was a pretty big hit. I'm not asking for a million dollars or anything like that, but I'd like to be able to cover costs if they come up. What do YOU recommend?"
Let them speak after assessing what you mean. They may ask if you've visited doctors or anything like that, and you say.
"No (or yes if you have), I've not felt a need yet. But I do know that problems don't surface until a while. What's fair to you?"
From here, the agent will either tell you that they will take care of future issues (which I don't recommend agreeing with), or they will go ask their manager, or they will blurt out a number. In my opinion, any number above $500 is probably fair for your inconvienence.
If the agent says they will take care of future issues, say this,
"I understand, but wouldn't it be easier if we just took care of this now, that way we are both satisfied and done with the issue? Like I said, I'm not after a big lawsuit and all that. I just want what is fair."
From there, they'll probably give you a number, and again, its your choice.
Its just advice that I've been told, and it works well. Also, it is legit, and most importantly it IS fair. I've been hit a few times (luckily never my fault, yet), and each time I approach the issue this way, and each time I've received compensation. Also each time I've had to spend a bit of the money on ice packs, muscle tissue massage, etc. So, it is fair to be compensated.
I hope that helps. IMO, unless the damage cracked the bumper, I'd just buff it out. The way drivers are these days, it is going to get tapped again. Especially with our exceptional braking abilities.