Oh my goodness, I feel for you. I have had bilateral facial swelling on a few occassions in the past, but it always went away. Once when I was in the hospital for a long covid situation, the doctor told me it was because I gained some weight--maybe just a few pounds, but certainly not enough to cause the swelling. I now have facial swelling on the lower face, on both sides since October. And lumps on both sides of neck. Just woke up one day and there they were, just like the swelling of the lower face.
CT and MRI scans come up with buccal fat. However no one knows why this happened so suddenly. My weight has actually gone down, so its not the cause.
I see a Rheumeotolgist next week on the advice of an ENT doctor. My salivary glands are fine so its not that. He thinks I may have an auto immune condition. I look like a chipmunk. Also still suffering with profuse sweating. All this after Covid. I pray for a diagnosis and a cure. Take heart, you are not alone, and we can empathize with you.