This morning when I woke up my lip was fine, but as the day progressed my lip started to get red and a little swollen and developed these bumps, which slowly started to look like they were filled with pus. It doesn't hurt, but I can obviously feel that part of my lip is swollen and tight. If my memory serves me correctly I have had this once before (years ago) and it was in the exact same spot and left my lip a little discolored in the area. What could this be? Cold sores?