Car renting dispute, need help urgent

I'm 18 and rented a car but not from any rental company, found this guy on social media. I asked for insurance, and they said they are private and can't sell insurance but said they have half insurance that covers the opposite side if an accident occurs. I rented for 2 days and had an accident with it i called the guy i rented from and he came by told me the car isn't his it was his friends car and he did not inform his friend the car's been rented, he tried to convince me to tell his friend i borrowed the car but i said no. The ower is a car dealer and apparently they also privately rent cars. and now they want me to pay 22000 dollars since the car is totaled. Checking with the insurance company the car has full insurance. The accident is probably at my fault since i was turning and the other car was going straight but i was too scared and lost of the memory of it. Also i live in MA. I have been so stressed from this someone pls help. What do i do. All i said to him was I'm only 18 and not financially independent so i can't make any decisions my parents will like to go through the legal process of wait for police report and insurance company however he said that if i want to wait i have to pay 50 a day of compensation lost since it supposed to be rented out. Pls help.