I am sure you have heard this from everyone and don't want to hear it again but you should try and quit or at least cut down as much as possible. My Dad was a smoker and had the same thing happen. The doctors said if he insisted on smoking that he should try and wait at least 1 1/2 - 2 months if he could. I think you should just never pick them up again and especially since you have already had a collapsed lung. You will breathe better, smell better and won't smell like an ash tray to people that don't smoke plus, you will save a ton of money. I wish you the best of luck quitting.