This happened to my dd8 about two years ago. We noticed in on a Sunday but after the peds was closed for the day. I called and spoke to the on call dr and he told me not to wait until the next day but to go to the er (no urgent care places here, just fast track at the er so essentially urgent care). The er doctor said they get this at least once a week. DD couldn't wear earings for a few weeks and she had to take antibiotics for a week. Since then we switched to more of a replacement button back and dd hasn't had any problems. The same think happened to my sister once when she was 12 or so but she is now 46 and hasn't had any problems since.