Filthy-looking blackheads feed the misconception that acne grows on grime. In reality, sebum tur the color of mud when exposed to air.

• 看上去脏乎乎的黑头粉刺让人们往往误解为粉刺就是在尘垢上长出来的。事实上，皮脂在暴露在空气中时会转变成泥土的颜色。