Allow him some space.
When you saw him, you should have told him the truth: you were worried, you missed him, you went out for a walk in the hope of seeing him “by chance”. Denying the truth and invalidating what he correctly perceived, only undermines trust. There is nothing wrong for a parent in being worried about a child, in fact it’s the contrary which would be repulsive. A child may say, I’d rather you had not come to search for me, or may say, please next time, if I go out, it’s because I wish to be alone; but that’s all. And no bad feelings will arise.
Don’t make a big deal that he smokes from time to time, chances are your own grandfather or great-grandfather smoked. Yes, that was before the health damage from tobacco was known, but everything does damage, even medication we take it when it prevents a worse danger. Watching TV is awful, but a person in the hospital may feel distracted from pain by watching tv and so we encourage. Try to think of his innocuous rebellion that way, after all he has not done anything criminal, not even illegal, and i suspect, not even assur. Thank G-d, but also give a little credit to him, he has free will after all.
Your son believes you want to control him, and actually, his belief is not completely unfounded. Leave him some space, everybody has mood swings, most people have smoked in their life, we are on the internet this very minute, and yet we have not become homeless drug-addicts or criminals. Don’t play a blame game, let him take his responsibilities without running to clean up his mistakes, but don’t invade his space either, be very respectful and don’t lie, and in twenty years he will be asking *you* for advice with his teenage kids. Be hatzlacha.
PS How are your other kids doing? Talk to them, for their sake but also because sometimes siblings have very valuable advice.