DEFINATELY do not smoke under any circumstances with a recently collapsed lung. At least for now. When your lung recovers from collapsing a few years down the road, then smoking is fine. I am a huge advocate of ingesting cannabis through brownies, because it's fun, easy, and you will absorb 100% of THC rather than the 60% through smoking.

Easy method is to get a box of brownie mix, and mix in anywhere from 1/16-1/4, depends on your preferences and the quality of the weed. If it says to use oil, put the predetermined amount of oil in a saucepan on the stove, allowing just a smidgen more oil than the recipe calls for, add finely chopped weed to the oil, allow for it to simmer on medium low for about 20 minutes until it turns a dark brown color, scoop out or filter the weed from the oil, place the oil in combination with the rest of the ingredients, and cook as directed. Might taste a WEE bit funky, but it is WORTH it. Depending on the weed, one brownie can last anywhere from 8-12 hours, and is more physical than mental. Kicks in in about 1-2 hours on an empty stomach.

ENJOY!

May I ask how your lung collapsed?