So i just found out the cause of my deep cystic acne was marijuana , i used minocycline , retin a , megadose vitamin b5 , vitamine d , magnesium and so on and still had very deep cystic acne.But i realised at some point that when i went to my mothers house or my dads house for a while i had 0 acne my face was clear.So by eliminating every variable i could think off like sheets , pillow cases and eating habits i realised that the only constant that i broke while i stayed there for a couple of days was that i did nt smoke weed.I stopped smoking weed and have been acne free for almost 3 weeks wich never happened in my life.So it seems that weed was the caused of my acne ... took me a long time to figure that out since i have been smoking weed almost everyday for the past 10 years ... So my question is this , is thee anyway i can smoken weed and not get acne? I mean i am not sure if the smoke is the problem or is it the chemicals in the weed that drys my face or something , will smoking it in a vaporizer reduce it?Will eating it help ? Anyone have experience with this problem ... I love my weed man seems like a rough trade clear skin but no weed.Dont get me wrong il choose clear skin but would still like to enjoy some weed once and a while you know.
I have the same problem, thankfully I only do it maybe once every 2-3 months but when I do I always get a flare of acne the next week.
Why this happens is hard to pinpoint, there are chemicals apart from thc which yes, may be bad and could make you break out directly. Some of the chemicals are released in the smoke, so yeah vaping it *might* make you breakout less/not at all.
Also, smoking weed increases testosterone in the body in which high levels are linked to acne, and which is why hormone drugs (contraceptive pill) works for some females. So it could be indirectly linked to the testosterone surge you experience after hittin' da grass. In this case, I don't believe the way you use it would help.
The chemical complexity of weed means it's hard to say which aspect is causing the acne. So you won't know if its the way you're using it or just the actual substance itself until you play around with it. The good thing is that you know, so that if you have an event coming up you can always plan usage for your skin to be clear during that time. 
hahahah
Have a look on some stoner forums because I know there are topics about the issue there.
I wish I had stopped smoking weed before going to extreme measures to cure my acne, it probably would have done the trick. That was the only thing I smoked regularly. However, I tried smoking cigars a few times, and that always made me break out like crazy too. So, I think it's the actual 'smoking' part that causes the breakouts and notthe weed itself, if that makes sense.I would definitely try eating itor maybe drinking it in some stem tea.