Wow, you poor thing. I really hope you feel better soon. I've been in the terrible position of having no insurance, but in Canada, it means you can still get all the basic treatment you need for things like doctors, hospitals, and xrays (*phew*).

I can't stress the importance enough of trying to find him. His insurance should be covering your medical costs. One important part of going to a Dr. right away is that it's your documentation that these injuries are from the accident. If he is ever found it's important for legal purposes. Even if for now all you do is basically report the accident and pain your feeling to the Dr. (Ice/heat it, take your anti-inflammatories, and see if he feels xrays are absolutely necessary at this point). Get all the info you can right away, while witnesses memories are fresh too, including writing your own reports up.

The other important reason, which might seem pretty extreme to bring up, is cases like Natasha Richardson's highly publicized death from a skiing accident (even though she didn't wear a helmet and I'm hoping you were). This tends to be more of an immediate concern as far as I know, but things can happen to the brain that we don't feel, or show many symptoms of, that have very dangerous consequences (like bleeding in the brain). Extreme, but it should be kept in mind when we have accidents.

Good luck. Stories like this always scare me so much.