Is my lip infected? and if so what should I do about it?

I have braces and recently went in to get a rubberband around a tooth so they could pull it over. Well a tiny piece is sticking out, and rubbing against the inside of my bottom lip. So it's been irratated since last friday. No biggie I have delt with a cold sore/irratated kind of lip thing inside my mouth before. Well yesterday I ate mc donalds (chicken mc nuggets and fries) and with in about 30 minutes after eating said food my bottom lip puffed up on that side. It was big red and a tad white, but it didnt hurt. This morning the swelling had gone down, but it was kind of big, white-ish and a little yellow. I just took a nap and now it hurts and is inlarged again. I ate before my nap a turkey sandwhich and some beef jerky. I don't know if that helps but I have no idea what is wrong with my lip. Can anyone please help me? Thank you in advance!