Swelling under chin for about a month

Hello,

Have been suffering from some weird swelling under my chin for about a month.  Have some swollen lymph nodes but my main concern is this crazy are under my chin that looks like a triple chin.  It is "boxy" looking when I swallow.

I have been to urgent care twice.  The first time, I was diagnosed with a sinus infection and precribed flonase and augmentin.  Today I went again, and was given amoxicillin that I probably won't take for "acue pharyngitis."  Any ideas as to what is going on here with this area under my chin?

Link to pics:

http://imgur.com/a/pyW1G

Thanks!