I have a big bruise on my stomach and don t know where it came from. There s a hard round center that is yellow, like its an older bruise but around it is almost 2 inches of all very dark purple, like it was bleeding profusely under the skin. I wouldnt say it hurts to touch, it more or less twinges I guess you could say, every once in a while. What could this be and how can I treat it?