A hickey, kiss mark or love bite (referred to as slag tags in certain parts of the UK), is a bruise

Bruise

A bruise, also called a contusion, is a type of relatively minor hematoma of tissue in which capillaries and sometimes venules are damaged by trauma, allowing blood to seep into the surrounding interstitial tissues. Bruises can involve capillaries at the level of skin, subcutaneous tissue, muscle,...

 or mark caused by the kissing or sucking of the skin. While biting might be part of giving a hickey, sucking is sufficient to burst superficial small blood vessels under the skin.

Hickeys typically last from four to twelve days and may be treated in the same way as other bruises. One way to help the hickey heal is to put a block of ice on the affected area; another way to treat the affected area is to rub it down with the edge of a coin using oil or lotion as lubrication to avoid skin irritation. This will cause the blood vessels beneath the skin to break up and disappear sooner, although this will only help if the hickeys have been present for under 10 minutes. They can be covered with foundation, powder or concealer. Another method of concealment is to use an article of clothing such as a scarf

Scarf

A scarf is a piece of fabric worn around the neck, or near the head or around the waist for warmth, cleanliness, fashion or for religious reasons. They can come in a variety of different colours.-History:...

 or turtle neck.