Hello, for the past 3 days I have been experiencing swelling on my lower left gum behind my second molar. When I was 15 I had all 4 wisdom teeth pulled out. For the past week I've been battling the flu I am on the Z pack it has helped with my flu symptoms but not my gum pain. I do brush twice a day but when the brush hits the gum area it hurts. Does anyone have any idea what can be the cause of the swelling. I don't eat on my left side now cause it hurts , I do plan on going to the dentist when am better.