Am I allergic to my lip piercing?

I have had my lip pierced for about 4-5 months now. My healing process was really bad with swelling and what not. But for the past 1-2 months my piercing is extremely itchy (i have not changed the piercing) and so is the whole outter lining of my lips it looks like i have a koolaid mustache :( .. I have been to urgent care a couple times to get prednisone shots because my lips will swell till they are purple, itch and get disgustingly dry I cant stand it. They said its an allergic reaction to something. I just can't figure it out and I've never had this problem before. I love the piercing and dont want to take it out, but if anyone else has had this same problem i'd like to know if there's anything I can do. Thank you for your time