I got my cartilage pierced at Piercing Pagoda, with a gun. (i know, its bad)

My brother threw a pen and pillow at me, and it hit my ear (longs story). My ear is now red, and hurts a bit. I had it pierced on Nov 7. Its Nov 14 now. lol, is it infected? Uh, i dont know if it is swollen, its just red, and it hurts. If its infected, how can i heal it?