I was feeling totally fine, and about 20 minutes ago, I felt a tightness on the side of my face, below my ear and down my jawline. It is dramatically swollen--a raquetball size lump. I can't tell if it's my gland, but it doesn't seem so. Could this be an allergic reaction to something? There is no noticeable bite mark. I feel fine other than the tightness. Any ideas what might cause such rapid dramatic swelling?