Hemangioma after a auto accident of the back a car hit the back of my car?

Hemangioma? Might you mean "hematoma" (bruising, swelling) instead of hemangioma (an abnormal build-up of blood vessels in skin or internal organs -- most appear in childhood)? It's not unusual to have bruising after an auto accident, but if you also have ongoing pain it's a good idea to see your physician. Depending on severity, the er or urgent care center if your own doctor isn't available.