Do you have medical payments coverage on your own personal insurance? You will need to open up a med pay claim with your insurances company. They will subrogate the claim and get the money back from the liability company.
In most cases doctors will not accept the liability coverage of the person that hit you for a couple of different reasons. First of all liability payers will only pay in one lump sum at the end when treatment is done. Secondly, often the insurance companies will pay the patient directly, that means the doctor will never get paid and the patient buys a big screen tv on the doctors tab. That happened to me last month costing me $1841.