Not in any meaningful sense. Rep Steve Buyer was full of shit when he claimed that smoking lettuce would cause the same problems as smoking tobacco. Nicotine is fucking dangerous, which is why they don't recommend people switch to chewing tobacco. It's not the smoke.
I only know because I have a friend that has two thumbs and a Medical Marijuana licence.
A good bong rip from a stoma hole is possible but you may need some petroleum jelly to get a good, air-tight seal. You'll have to hold your nose to get suction.
Pot smoke contains carcinogens when burnt. Any herb/plant/whatever you burn is carcinogenic simply from the process of turning into carbon. But the carcinogens are not inherent to the plant, so yeah weed if taken with a vaporizer or eaten is probably the least detrimental drug you can do. You won't end up with a stoma from smokin' weed unless nature was gonna assfuck you with one anyways.