What Causes Swelling And Pain In Cheek?

i had cheek implants removed 6 yrs ago. I had a root canal in Sept. Oct. I started swelling on the left side of my face. I have had CAT Scan - MRI and numerous xrays of teeth. No answer....It is painful... I am seeing an Oral Surgeon on Tues.....My face swelled so bad in Nov. that Urgent Care sent me to the hospital. My eye was even black. Any ideas? Yvonne