I was diagnosed with left tonsil and lymph node involvement 3 years ago.  I had the neck disection after the radiation and chemo.  My understanding is that if you are 
HPV+ the neck disection is not necessary.  I was not 
HPV+ so had the surgery.  I would be happy to talk to you anytime.  Call me at 732-687-3518 anytime.  All the best.
Rob Jaffe