Imagine a hair follicle as a tall chimney; the pore will be the opening at the top of the chimney. Sebum is a mixture of grimes consisting mostly triglycerides, wax esters, squalene and free fatty acids. It travels up the follicle, sometimes carrying with it dead skin cells, and exits through the pore. When the sebum can’t get out, it results in inflamed pores and build-up of P. acnes bacteria. Left untreated, it will lead to acne breakouts.