Should I come clean to the cops?

So I was Outside of the club right after they closed waiting for my brother to pick me up and met this tall Puerto Rican kid- pretty young looking, maybe 17/18. He said he was waiting for his friends and right when he said that his 2 friends showed up, one heavy Puerto Rican kid about the same age as the other kid, and an African American kid, around my age- in which I actually saw him inside the club and we went outside we smoked a joint together. IIm a 19 year old Caucasian. We all started talking and it ended up we have a ton of mutual friends so I felt very comfortable with them. We were trying to pick up girls and whatnot until we got near this one kids apartment ccmplex and he said he was "mad tired" so I non shalantly walked with those kids to his apartment. I had maybe a gram of weed on me and they knew that cause we were going to smoke really quick before they left. Right when the African kid said peace out, they all started jumping me and I don't really remember what happened. They wanted to steal my money but I had no cash on me and they stole the weed and busted my iPhone 6plus. I told the cops everything beside the weed part. Basically just told them I was hanging out with the kids. When the cops were questioning me, they cotton swabbed my mouth to see if I smoked (takes 2/3 days for result) should I come clean before they get the results?

Yes.

No. You won't get in trouble for lying about smoking, atleast I doubt it. Just because your a smoker, doesn't mean its ok for black gangs to beat the **** out of you and steal from you.