C.S.
I have been working with children for 3 years. I have 2 of my own. My youngest has one right between his eyes. It bugs me, but I know that it is no big deal. Your doctor is right. It is just a matter of the location of the veins and the thickness of the skin. The better you can see a vein, the closer it is to the surface of the skin. Many times veins are also harder to see becuase of things like fat and how fairness of the skin. It really is nothing to worry about!