My 4 yo son is very fair (blonde, blue eyed). He had a stork bite at birth, and it's still visible to this day. You can also see his veins through his skin as well. This is common for fair children and people. I wonder if they are more visible now since it's the dead of winter, and her skin isn't exposed to the sun as much. My son's are pretty visible now, but will fade some when summer comes and his skin gets a little darker. At any rate, I would mention it to the pediatrician if you are really worried.