Xanthos,
I find I get a drier throat with e-misting, it does appear that it's caused by the PG. I counter it by increasing my water intake during the day and also by sucking a sweet. I prefer tic tacs, you might like something different. The action of sucking on a sweet has a soothing action on the mouth and throat, the sharp mint flavour of the tic tac also dulls the raw feeling, same as menthol cigarettes do. I used to change to a menthol cigarette when I had a cold or sore throat.
If your cold gets into your lungs and you get a chest infection, I think it would be best to not put anything into your lungs until the infection is cleared up, not even e-mist.