Why is my nose piercing so sore?

i got my nose piercing in may of 2010, so over a year ago, and i didnt touch it, i just had a small keloid bump for about six months, then things were fine. about two days ago, i went back to the place i got it done at (alternative arts piercing and tattoo) and i had them switch the original stud to a 20g hoop. i didnt go up or down a gauge. now, it hurts so bad to do anything around it, and i have the keloid bump still. i watched the woman clean the hoop extensively before she put it in my nose, so i know it was clean. i love how the hoop looks, but its so painful right now, i dont know what to do. i dont even wanna touch it. i have done a few salt water rinses, and i just wanna save my piercing. HELP.