Okay so I was taking my bra off and noticed my nipple looked odd, so I lookesd down and there were black spots..I squeezed one and it looked like dried blood. The other night me and my SO had rougher sex and he sucked on them, could that have been why I had blood? Did he suck to hard? It freaked me out. I tried looking it up and didn't find anything. I was hoping some of you ladies would know anything.  Thanks for the help.