Weird Spots

My name is Diane. I am 24 and relatively healthy...around the begining of Nov./08, I noticed I had a small pinkish brown spot on my belly, just below my right breast, but it was on my belly, not my breast, anyway, it was about the size of a pencil eraser and there were two smaller ones about the size of a pin head, one on top and one on bottom, but none were touching.  It has been almost four months and they have grown into eachother, now about the size of two pencil erasers, and jagged looking edges, not a perfect circle.  Also, there's a small one on top and bottom of the big one, just like before.  No iching, burning, hurting...nothing.  What are they?  Will they keep growing?  Could this be cancer?  
   With deepest concern,
              Diane.