Gravy Tongue

Good morning!

My husband is almost 8 months post Radiation.....he has 95% taste back and is tolerating everything - even hot/spicy items.  He has regained all of his saliva on the sides of his tongue, and we thought some on the main part.  But a few days ago he started saying that he felt like he had a thick gravy on the roof of his mouth.  Well, I felt the roof of his mouth and it's dry.  So, after some looking and poking around, we believe that it's the main part of his tongue that's producing this "gravy" substance.  We are huge kissers, so the feel is more slippery than what I'm used to when we kiss, but it doesn't seem to be thick, like he explains it, and there is no color to it.

Has anyone else experienced this?  Is it still the healing process?