The physio started working on my neck at about four weeks, stretching and mobilizing scar tissue and massaging for lymph drainage. Best of all she taught me how to do it myself. Four months plus after a radical neck dissection and some great physio help there is still a small amount of swelling that will likely be permanent because of the extended nature of my surgery.
As Mark noted, elevating the head of the bed is a good thing for drainage.
Hope you have a physio referral in your hand soon.
All the best, Fran B.