failed to pay car loans, what will happen next?

The problem was my friend had a bad credit, so I bought the car for him. I purchased it under my name,but my friend was the one paying the car's loan. Now my friend can't and failed to pay the car loans for several months already and I can't contact him. What will happen next? Will the lender repossess the car? How bad will it affect my credit score? Should I or why shouldn't I filed for bankruptcy? What's the benefit if filing a bankruptcy? EMERGENCY! Please answer every questions please!!!!