These occur when the ends of tiny capillaries break and a small amount of blood becomes trapped under the skin. This usually happens during or after illness or when there is some weakness in the blood circulation. It is nothing serious or to be ovely concerned about. In a healthy person millions of blood vessels become damaged each day, but not all of them can be repaired. Those that are not may show up if they happen to be near the surface of the skin. Others may remain hidden.