after having sex one time the day after it i noticed brown blueish bumps on the front of my penis, and these bumps have been spreading to the back, now my penis hea looks a little brownish, adn i did test for STDs everything but the docters say ther's nothing wrong so now i think it might be ishemia, beacause i had sex to rough a vein got damaged, could i be right? and is there anything to threat this?