I was in a car accident and received several ijuries 4 hernaited disc to my neck and one herniated disc s-1 and bulging disc l-5 and at t12 bulging disc. And a couple of months later I was rear ended by another driver she admitted fault to her insurance company can I sue for aggrevation of previous injuries. If so how to go about it

Step one is hire a personal Injury lawyer and let them do the rest.

Yes you can sue, but you don't sue the insurance company, the sue the driver. She notified insurance company that she is being sued. If she is held liable at the trial, insurance company willl have to pay. Now the insurance company will have an attorney there, so you will have to have an attorney.