OCD and Smoking Please help

I went to buy a pack of cigarettes yesterday and on the way there I bit my fingernails. I wanted that pack to be the last pack I ever bought and quit smoking but because I bit my fingernails, I tell myself I have to go back to the same store, only this time not bite my fingernails and then I can quit. It's like if the wrong thought gets stuck in my head while I'm smoking or on the way to get cigarettes or whatever, then I tell myself I have to buy a whole new pack and start the ritual over. Any advice on how to get around this? I would really appreciate the advice.

hmm i don't have ocd myself so i can't really give pro advice, wear gloves maybe on your next trip so you don't bite your nails?

You should try some sort of anti-nail biting nail polish.
Just from a random google-
Amazon.com: Mavala Stop-Nail Biting and Thumb Sucking Prevention, 10ml: Beauty

I tell ya, it can be quite effective. The polish is transparent and the taste is bitter enough to make you not wanna keep at it. Harmless to so not like your going to poison yourself.

I've been a chronic nail-biter my whole life, and so is my dad. It's all willpower. Start running every day, and you'll start to notice VERY FAST how smoking is affecting you. That's how I cut down drastically.

Forget the ritual. I quit smoking.