Why is the blood draining from the forehead black?

Bloodletting in the forehead is black in color, which is considered by Chinese medicine to be the presence of blood stasis in the body.
Bloodletting on the forehead is a common physical therapy in Chinese medicine. Bloodletting, also known as blood pricking, is done by needling some acupuncture points or localities to release blood. Blood can be released at Yangbai or Yintang, which is one inch (about one horizontal finger) straight up from the pupil, and Yintang is in the middle of the two eyebrows.
Bloodletting therapy is suitable for treating heatstroke, headache, tonsillitis, neurodermatitis and boils. Bloodletting on the forehead can relieve pain symptoms. The black color of the blood suggests stasis.
After bloodletting on forehead, attention should be paid to the cleanliness of the wound, avoid contact with water to prevent wound infection. Daily diet should be light and avoid spicy and stimulating food. Pay attention to rest and adjust your daily life.
Bloodletting therapy should be performed by a professional acupuncturist, not by yourself.