I recently had a sharp pain in the palm of my hand. When I looked down I could see a big vein bulging and it looked like it was moving. It was an intense pain and lasted for maybe a minute. I thought it could be a cramp? But now where the pain was it is swollen and bruised and sore to the touch. I did not hit it on anything. What could it be? Could it be a cramp or maybe a blood clot?