There is a hard string-like thing under the skin of my penis. It starts at the base and runs about 3/4 the way up the shaft. It's on the top of my penis. It's like the size of a vein but it's hard, un-like a vein. Anyway, this "thing" feels bruised when you press on it gently. I am wondering what it is? Is it possible that I hurt a vein, even though this is hard, un-like a vein. Or could this even be some type of ligiment that I hurt?