How is the hickey formed?
Generally, kissing does not produce hickeys, which belongs to subcutaneous congestion. There are two reasons for hickey, one is the mechanical behavior of teeth, and the other is the negative pressure of suction.
Because the kiss is too hard, the skin is congested, especially in the delicate parts of the skin like the neck, and it is easy to form a hickey because of the hard kiss.
Therefore, the pressure outside the human body is reduced, while the pressure inside the human body is unchanged, and the blood in the capillaries will flow out from the capillaries, forming a small blood clot on the skin surface of the human body.