I was charged for marijuana and had none what should i do?

[Justin]

So I was in my friends car he parked in a parking lot at a walgreens this cop shines a light at his car as he was about to pack a bowl I'm in the back well we all got searched I had nothing my friends in the front one had a pipe and a bowl about and the other one had a bowl or two after that we waited for tickets they gave us all possession of marijuana and possession of drug paraphernalia I don't understand why I got it seeing I had nothing and everyone admitted who had what so what should I do