I'm late to this thread, just wanted to chime in as I also suffered a pneumothorax 2013, the doctors screwed up every part of my treatment, I spent a 8 days rather than the usual 3-4 days in hospital and they allowed air back into the cavity which left me with a squelch in my chest for a week after I got home. As others have said vaping flower is still inhaling thc in an oil form, amd it was the additives to carts. I find if I vape heavily I can still feel some chest pain at the end of the day so I normally take a day, maybe two off then. Your lungs will natuarlly process and expel any built up oil and particulate from vaping which deposits in your lung. The problem is your body can only work so fast, for those of us with sensitive lungs we really need to pay extra attention to what we vape, the equipment we use and how frequently we vape.
I found vaping with my RBT splinters and the standard direct path stems, even the spiky ones caused way too much irritation for me and after the switch to the lamart nub stem a lot of the irritating ceased. You can see after a few days how much flower particles deposit in the nub stem as the vapor it redirected through, I've not had as many problems with dynavaps but there is a huge difference in airflow and how the heat the flower.