One of my first symptoms to show was the development of splits in my tongue(fissured tongue). I was told by my dentist that this was nothing to be worried about and was related to a condition called Geographic Tongue. GPs never commented on ssplits in tongue although I mentioned it to them.
Came across this piece of research recently ....B12 levels were lower in the the group compared to the control group. I still think that B12 deficiency can trigger fissured tongue.
Old HU threads about B12 defic and tongues
I'd be interested in case anyone else finds any research that links B12 deficiency with fissured/geographic tongue.