I blacked out and hit my head over a month ago. I had a large softball size bump on the back of my head. I went to the hospital and they did a CT and they said the results were negative. But I still have the bump, the size has gone down but I have horrible headaches on the size of the bump and the bump is still sore to the touch and I am having problems with short term memory . Is this normal should I go back to the hospital