Are there any smokers or people with knowledge of Cannabis here?

Contrary to much false information put out by drug addicts and head shops, smoking marijuana is damaging to your lungs, at least comparable to smoking tobacco. Much damage is permanent and irreversible, but not all. If you stop smoking right now, at least the damage won't get worse than it is right now. Over time, your lungs will regain much of their function, but never 100%.