Looking for more info on a "severely atypical compound melanocytic nevus."

On July 7, a dermatologist removed a small freckle/mole from my left calf. It was about 2 mm in diameter. It came back as severely atypical. It was dark but not too asymmetrical. I'm going to get a re-excision tomorrow. I am now extremely worried about other small freckles on my body and about melanoma. In addition, this abnormal mole was located on my calf, which has no pigment (I was born without pigment there). I try to stay out of the sun and have never been in a tanning bed. Help! I'm freaking out.