I have had what's called geographical tongue for over 25 years. Lately I have been experiencing a burning feeling right in the middle of my tongue. My dentist told me I had dry mouth and to begin using Biotene for dry mouth last yr. I went bk 2 weeks ago because it started to bother me again and now he said I am lacking in Vitamins D and B 12. How long does it take for a vitamin to get into your body. I also have 5 hernias, I don't know if they are causing extra acid in my stomach could they be causing the burning on my tongue.