I Swallowed A Piece Of Plastic That Was Serve To

I swallowed a piece of plastic that was serve to me in a burger, it was a seal from a mayonnaise bucket... There is a scab/sore that has developed on my head, it's itchy and flacky! What should I do? Would the sore be a reaction to the plastic? What about my digestive system, will the plastic pass or irritate? Please help...