It will come back.. not immediately so don`t be disappointed that when rads stops it doesn`t return... it`s a slow slow process. I am now 13 mos out of surgery 10 mos out of treatment and I am still missing most of my sweet, and salt comes and goes. But natural foods taste best. Processed foods taste like CRAP and pop like turpentine. It can be depressing but you will get through it. DO try to maintain your swallow as much as possible even if it`s through drinking luke warm water or ensure. Good luck...
I am not sure if it was mentioned before but radiation is cumulative so when it stops it still gets worse for a few weeks so don`t freak out when you dont feel better. Take care and try not to despair.