Hi all, just to follow up, I'm happy to say the dry mouth has went away, and the inside of my cheeks feel smooth and well lubricated again. I started taking Thiamine (Thiamax) along with a B-complex vitamin for the past few days and my symptoms are now totally gone.
I can't say with 100% certainty that Vitamin B deficiency is what was causing this, although it's likely. I spent the weekend without drinking any espresso, and only drinking cafe bought coffee with milk and sugar. Today I'm resuming the espresso and will follow up if this feeling comes back.
I think I also have been a bit under nourished lately which has been putting stress on my body. I'm trying to lose 10-15 pounds, and have significantly reduced my caloric intake, having only about 2 meals per day along with generous orange juice intake. I've come to the conclusion that how much I'm eating is probably not enough. I'm 6'2 and roughly 215-220 pounds.
Thank you to everyone who chimed in with reassurance and advice. I really appreciate it.