A few months ago I noticed on my left leg below my knee, what looks like a grid on a part of my leg.?

It is almost as if I can see through my skin. The grid looks like my veins or arteries. I would appreciate if a doctor could answer my question about this. My skin is smooth where this gridlike mark is.. It is not varicose veins, because I know what those look like and are. This mark on my skin on my leg makes me wonder what could it be!? It does not hurt. It is just bewildering to me.