Suggest Treatment For Lightening Of Skin After Gamma Knife Surgery

I had gamma knife surgery on April 21, 2011. Some of the pins were located on my temple, The skin has lightened quite a bit and ithe area is becoming larger. Is there anything that I can do to prevent it from spreading? I was told to massage it and it would darken. It only darkens for a few minutes. Does the fact that I am an African American with dark skin have anything to do with it? I am 72. I weigh 149 and am 5 5 . I have had 2 bouts of breast cancer, one of lung and one of windpipe.