I've always thought of a hickey as a love bite. It's also called a bug bite, kiss mark or a bruise. Bruise? Guess that depends on how you got it. You can acquire a bruise a number of ways but a hickey is usually caused by suckling on the skin, which causes small blood vessels to burst under the skin. I think you typically see hickeys on the neck and chest area. Ever had one?
According to Wikipedia they can last for up to twelve days.
Did you know that there are sites out there that tell you step by step how to give a hickey?