I dropped my iphone on the first day I got it, and the back of the phone is cracked. Is there anything I can d?

I dropped my iphone on the first day I got it, and the back of the phone is cracked. Is there anything I can do to get a new one? I understand that it was idiotic, but i was sitting in a car for 5 hours and when i got out of the car, it fell on the concrete.