What should I do?

I had breast cancer, had a lumpectomy, chemo, and radiation. I finished my radiation in July of last year. My doctor started me on tamoxiphen and then changed to arimidex. I've been on it for about 6 months.This weekend I noticed the coloration on my breast had changed dramatically. The skin had faded to a suntan before. Now, all of a sudden it looks like it did last summer. I don't know if this might be a reaction to aramidex or if I need to call my radiation doctor or cancer doctor? Has anyone experienced this? Any info will be appreciated.