Blue veins are showing....why?

[flicks_az]

I've recently noticed a blue vein showing up from the back of my leg. The part that bends in order to walk. This looks unatractive and i'm wondering why is this happening now? I work at a fast food resturaunt which means i'm constantly standing and walking around. Now i hear that veins pop out when you excercise or something like that but it doesn't pop out. It just kinda shows. Ya know the vein that never really goes away. It just doesn't seem normal. How can i get rid of it and what does it mean?