The major cause of acne is P bacteria present in acne skin. Hardened oil ( acne impaction) covered with layers of dead skin, without oxygen is perfect condition where P bacteria thrive.

How to eliminate P bacteria?

By depriving bacteria of it's food: oil and bringing oxygen to the skin (P bacteria can not live in presence of oxygen).
Several acne treatments and home regime will get rid of all these layers of dead skin and bring oil to the surface.
The best acne facial is when I take time 1 hour to extract all acne cause seeds. After 3-6 treatments, depend of skin condition, skin is free from acne. At that point, you will get recommendation how to maintain acne free skin (topical cream that will exfoliate skin and bring oxygen at the same time).

First six months is very important to keep skin exfoliated and free from clog pores. Sometimes some facials are necessary.
Several months is needed to keep skin in such condition to completely eliminate P bacteria.
Facial and home regime is supported by acne diet and recommended supplements.