Inflamed and Non-inflamed Acne
Non-Inflamed Acne: Dead skin cells and oil (plus other debris) form a plug inside the pore. If this plug does not become inflamed it can become a whitehead - a non-inflamed lesion under the skin, also called a "closed comedone. Sometimnes called "maturation arrest" acne, as it has not "matured" into a blackhead yet.
Inflamed Acne: As the oil and the dead skin cells build up. they put pressure on the cells surrounding the pore. Because this material contains a lot of P. acnes bacteria, the surrounding skin now becomes infected, creating a red bump that we know as a pimple. The medical term for this red bump is an inflammatory papule.