Lawsuit after rear ending someone

I rear ended someone back in June and they are suing my insurance company because they said it caused a back injury. My insurance policy has a $300.000 bodily injury so they are trying to settle within my policy amount. At the scene of the accident the guy asked me for $1000 instead of going through insurance which I denied. My question is did this happen to anyone else? What happened? Did your insurance company end up dropping you or your monthly payment end up increasing