Are visible veins on scrotum supposed to be normal? when is it varicocele? i feel some strange feeling sometime on left, like tingle, no pain though.

Here are some ...: Visible veins on scrotal skin are normal but with a wide variable degree, and they're unrelated with varicocele, which is chiefly on left side and usually invisible; if a large one, it becomes visible in standing like a bag of worms with slow moving, but disappearing in lying position. So, have Doc take a look and feel for verification.