Does smoking really increase your risk of a collapsed lung again?

Depends on cause: Risk of developing a collapsed lung again depends on why you had in the first place (i.e., its cause). Smoking in general causes destruction of lung tissue & reduces your lung function over time. It also increases your risk for having cancer. You should strongly consider quitting smoking - it may seem hard at first, but with your doctor's help, you can succeed. Give it a try & you will feel better.

Yes: Cough, emphysema, blebs, irritation, pneumonia, cancer and recurrent pneumothorax are several sequellae.