I too had this after my neck dissection, got so bad I had a catheter bag attached to my neck which I could drain at regular intervals, but after a couple of weeks it stopped. I am now 6 months out of surgery and swelling has completely gone down.

SCC type 1 tumor in left cheek aged 45
T2N1M0 - surgery 14/2/13 to remove tumor, skin graft from wrist, neck dissection. No rads/chemo.