The tongue will be an issue going forward. I had similar experience even with radiation shields in my mouth. Mine developed into a large ulcer. Keep your medical team informed. Yes keeping the tongue below tooth level helps. That irritation aggravates an existing problem. Great to know the cold is leaving and keep up food/water intake.

Age 55 HPV 16+ SCC, BOT 050613 Stage IV
great team at OSU
Tx 6 weeks of rad started June 3
8 weeks of chemo started May 28
RTOG Phase III trial Cetuximab group.
Treatment completed 7/16/2013
PET Scan completed 10/08/13
Results discussed 10/11/13
NED - Free but am I
Next part of the journey?
1year PET 10/24/14 NED
Good reports now 10 years out.