Just a little answer lol, sorry to hear, but it's very common, especially when the lymph nodes are removed or compromised from radiation, infection, illnesses, due to the lymphatics trying to drain downward toward heart level. It will go down somewhat, like a clogged drain, over time, and may comeback when the fluids gets built up ot from too many toxins, illness, infection, etc. I have a slight turkey neck, which went down significantly, but I'm almost 3 years out from a RND, and had two more since. Basically the lymphs are the sewer system for lymphatic fluids. Be careful with massage, until properly shown, since they have to be done with a certain pressure, motion, direction. They have lymphatic Masssge Therapist's experienced in this. Accupuncture helps some, so does light exercise to get the lymphs flowing, like swimming or walking while swinging arms above the heart, a trampoline, sauna, sweating, but like everything, check with your doctor before doing, and to rule out any recurrence or new cancer. It may be worse in the morning due to all the fluids pooling while laying down, so sleeping on an incline helps. Diet may also factor if you eat too many preservatives, chemical foods, and even some medications. I would not doub't that the gravitational pull of the moon has an effect on many fluids at night, like illnesses seeming to occur at night for unknown reasons, and heard that many moons ago. Anyway, I have not used any compress bangages nor any other treatments. There is one being done in Nova Scotia, Canada with liposuction for HNC lymphdemia.

Good luck.