Takes years upon years of accumulation to cause irreparable damage -- the 'scars' are still there, but they heal if you take it the hell easy.
Originally Posted by P.E.N.G.U.I.N.
If this behavior of 'holding it in' persisted, however, the least you can hope for is lung cancer aside from the many respiratory issues you'll be bumping into on your short lived journey to the grave.
Although, my father's been smoking marijuana since he was about fifteen, and he's now almost sixty without much visible damage to his health -- he doesn't wheeze; doesn't cough unless he took a fucking huge hit. Then again, he's been smoking out of bongs exclusively for the past fifteen or twenty years, and he isn't a heavy smoker to begin with.
He also doesn't hold the hits in for more than three seconds.
"I didn't inhale." - Bill Clinton
[ A Presidential candidate at the time ]
"Make the most of the Indian hemp seed, and sow it everywhere!" - General George Washington
[ A note to his gardener at Mount Vernon, on the year 1794 ]
"First they ignore you; then they mock you; then they punish you; then you win." - Mahatma Ghandi
[ Indian independence leader ]