Scab

A scab is a dry, crusty wound covering that forms to protect the wound from dirt and germs. It is typically formed from dried blood, serum, and dead skin cells. Scabs can vary in size and shape, and may be black, red, or yellow in color. Scabs can form within hours of a wound, and can take days or even weeks to heal. The scabbing process is a normal part of the body's healing process and helps to prevent infection.