I had a similar deal that went on for about 3 years. I tapped a guy going (literally, not exaggerating) about 3mph. I agreed to pay for his slightly scratched bumper out of pocket. He called me next day to say "I don't want you to think this is some sorta insurance scam, but my back is kinda bothering me, so I'm gonna go do the doctor". Famous last words...
2 year, 360 days later I get a call from my insurance company that he's filing suit. Insurance company wanted to settle, to which I said "go ahead, but know that this is a total fraud". They reviewed the file (they ended up totaling the car!), and decided that they'd had enough.
Depositions, testimony, lots of burned time. The offered him 15K right before it went to jury (why, I have no idea). He lost and got about 5K in medical bills, all of which went to a subrogration claim from his health insurance. In short, he got nothing.
The insurance company's lawyer (in house counsel) said "think of it as a civics lesson". In talking to him afterwards, his read was that plaintiff just seemed really unlikeable, and that's probably what sunk him. He was just a horrible witness. In the end though the system worked and he pretty much got exactly what he deserved...