I've been vaping on and off for a long time and I always go back to smoking because I get mouth sores. I am not allergic to pg. I use it in all my products and I've used 100 vg juice before and the same irritation occurs. Sometimes it takes days, or even weeks for sores to develop but I don't want to give up vaping. I just went out and bought an evod and some decent juice. Feels great to vape again, but the mouth is irritated at the spot where the vapor hits my mouth. Does anyone have an explanation for this? Could it be I'm using too high a nicotine content? I'm using 18 mg. I really don't want to go back to smoking ever again.