I know what you're talking about, it has nothing to do with the smoke. (that I know of)
Amphetamines induce repeated muscle movements, many centered around your head and neck (stereotypy). A lot of these occur in your mouth. What happens with me at least, I rub my tongue against sharp spots on my teeth almost subconsciously, and after several days of this white sores apear on my tongue that make eating and talking painful. Even when I'm aware of it, I still can't stop doing it. However, after the first week of constant use I build up a tolerance to these effects of amphetamine, and the sores heal fairly fast.
There are probably a lot of variations on this, like chewing on your cheeks, etc. I don't know of any way to stop this effect, other than building up a tolerance. Also, they think the 'appetite suppressant' effects of amphetamine are really the repeated muscular movements interfering with your ability to chew and swallow food, which confuses your body and makes it seem like you have no appetite.
Search for 'amphetamine induced hypophagia' on google and you should find some good articles on this if you want to read more about it.