Kyle,
Don't be afraid of the radiation. If you have to do it for a better chance to survive and never face it again, it is a good thing. Is it difficult? Yes. Is it survivable? Yes.
I had the same surgery as you but on my right side. Lost 1/3 of the tongue and did radiation on both side of the neck and from the front. I am 4 years out from the end of my radiation TX and still cancer free. I would do it all over again too if I had to!
The numbness faded with time for me and I have all sensation back.
Jim