Is it the entire side of your face or is it more pronounced in an area? It could be many things...depending on the area. Extremely swollen lymph nodes (there are thousands in the body, not just the "typical ones" in the neck, under the arms etc...this could be indicating an infection somewhere), it could be sinus issues, teeth issues, eye issues, etc. Oh...possibly ear issues also. For most of these things there would be some pain somewhere...but I know for sure that I don't tend to notice pain too much (my impacted and infected wisdom teeth didn't hurt at all...something gross had to happen before I even noticed!).

I think if it doesn't start going down within a couple days, then you should see a doctor. You can press (gently) on different areas to see if you can determine what type of doctor to go to. If that doesn't give you any ideas, then I would see a primary care doc.

Hope it gets better quickly.