Birthmark on the shaft of penis, should I continue with Picoway treatments?

I have a relatively dark birthmark on the middle of the shaft of my penis roughly the size of a dime. It looks like congenital nevus on Google images. I've done four Picoway laser treatments and have not seen much results, and it seemed to have gotten a little darker. Are there any other options? Should I continue with the Picoway treatments? Would surgical removal be a bad idea and could it make my penis smaller? Should I see another dermatologist or should I see a plastic surgeon? What laser?