text: a hicky is caused by sucking, the blood raises to the surface of the skin, which causes the skin to look bruised and discolored. There are rumors that you could possibly get tumors or blood clots from this however there is no need to worry because they cannot cause cancer. cancer is a disease, it is caused by low production of white blood cells that help your body fight of infections and bacteria. Most people who have cancer die because of some other illness before they die of the actual cancer itself. So you see it may be quite impossible for a hickey to change the white blood cell count in your body.....