So basically I struggle with both OCD and anxiety, and I went out last night and I am a non-smoker, but because literally all my friends smoke socially when clubbing they asked me to try it yes purely my decision, but I was drunk so I said why not I literally only had one puff and that was it and handed it back. But now I feel so guilty cause all I'm seeing in my mind are those pictures of lungs and stuff after smoking. Anyway my question is will I know have tobacco permanently in my lungs and/or will this affect me in any way? I understand that it's a bit of a stupid question but my paranoia won't let me get it off my mind.

You don't have to actually be smoking it to have damage... all that second hand smoke you inhale clubbing and otherwise does too. But that will have done far more damage than actually smoking one time only would have.

I would be more worried about your drunken behavior in smoke filled environments having deeper more long lasting effects than one actual cigarette you smoked. In addition, as was pointed out, maybe you should take heed of your paranoia and just stay out of smoke filled drunken environments PERIOD! Much easier to deal with your OCD, and anxieties without that stuff. Drunkenness and second hand smoke kills just as effectively as actually smoking.

Need help with that? It's out there if you want it.

Yes, I have fully learnt my lesson in regards to that just first night back at university and celebrating with my friends, I am not a regular drinker.

I will agree, just being in a club filled with smoke is almost as bad as smoking yourself. You need to stay in areas with no smoke, to best protect your lungs.

Lungs over time, can self clean but that takes years and years.

A bigger worry is the drinking which can do much more harm to your body,

Absolutely not a silly question. No, this one puff will not permanently damage your lungs.

I, at 71, don't have great lungs because I inhaled a lot of construction debris in the early 80s.
However, I live in a rural area. No vehicle exhaust, or diesel from trucks and buses.
No clubs full of smokers either.
Which one has healthier lungs, you or I?
No way to know.
I went to a museum as a kid and saw real lungs, healthy ones and smokers' lungs. The smokers lungs were black, and I mean BLACK, coated with tar, like a parking lot freshly tarred. The healthy lungs were pink.
Go out to restaurants and coffee shops instead.

The best cure for anxious ocd like this is education. Study it. Then this 'silly' question won't be silly, AND you will get it off your mind.