
Quoting
Mr. Knowitall
You are free to tell the school that your friend is lying and that you've only smoked cigarettes with him. I make no promise that they will believe you.
Given that you have already lied, if they have evidence that you were smoking your claim that it was only a cigarette isn't likely to convince anybody.
Given your actions, your friend's story, and your lies, yes, that's probably what they will conclude.
You will have to see whether or not the matter is referred to juvenile court, and if so what charge is made. As for the school, obviously, they can impose punishments, which will vary depending on school policies, what they can prove, and your prior record of misconduct.
Yes, you were. What you mean to say, apparently, is that nobody ran after you when you ran away from the teacher and school officer.