Hello Lowanne,

Don't ever feel bad about asking your treating doctor to refer you for a second opinion. It's Jack's life were talking about here. You have to be his advocate. Not all doctors have the ability to properly dx this diaease. Not all scans will pick it up. Be agressive asking questions.
I don't know if Mayo is a leading Head & Neck cancer center. Gary has posted a link to the major ones. If you look at some of his recent postings you will find it.

Best of Luck, Danny Boy