I am a woman. 38, years old. There will be like a layer formed on the tongue everyday. Why is it. When I brush my teeth, I clean the tongue also, at that time, I feel it goes, bt again during the day and night it forms again. And also the mouth the lips becomes very dry, I drink how much ever water the dryness in the mouth comes back. It's always there drying the night also. My sleep also gets disturbed a lot. I drink water in the middle of the night. Bt still the dryness doesn't go. Pls suggest. This is there from a long time. Pls suggest for treatment. Thank you.