Alternating hot and cold compresses? Gently press a very hot compress across your sinuses until it doesn't feel hot (to your face, not your hand), and then a very cold compress until it doesn't feel cold. Repeat 3-6 times per session, 3-6 times per day. This worked very well for me when I was pregnant. I used a bowl with steaming hot water and a bowl with ice water, and two large face cloths.

My midwife, who suggested this, also suggested adding a few drops of eucalyptus oil to the hot water and a few drops of lavender or lemon oil to the cold water, but I didn't.