So i was just looking over this website and there is alot of debate on this topic. But I suffered severe cystic acne on my back shoulders neck and sometimes mixed in with mild spotty acne on my face. I really only found relief once i started using a light scent free type lotion on my whole upper body after i showered. Gradually the severity of the acne declined it took about 2 months of almost worsened acne but then it started to shrink in size and severity it stopped on my middle and lower back then my neck..and my face was left to only one here or there. I still get small spots on my upper back near my shoulder if i dont shower after activitybut they never form a head if i stay clean. This worked for me thoughnote i exercise frequently and eat healthy organic gluten free no fruit juice so i doubt its from one approach.. But what i do believe was happening is that when you shower and dry out its important to use lotion i think it almost blocks the pores in a clean way that doesnt allow dirt to get in deep i feel that the skin when dry also gets inflammed which will make acne more severe for someso the lotion may helpsoothe it a bit. Idont know if sebum gets reduced long term considering its a hormonal action but it only makes sense that sebum production "frequency not volume" would increase with dry skin for the sake of retaining more water from leaving the body.

Heres something to think about before you question anyone on this site or in life have a good day. To look at anything objectively you have to realize the mechanism of push and pull, balance/harmony and the natural state of evolution and adaptations of everything in the universe. Where theres an action there is a reaction always, no matter if its measurable or not. In the same waythe body adapts when you take something internally or apply something externally by adding or subtracting from normal function.

(Sidenote: i have been unusually stressed recently and have only seen changes mildly in shoulder and face acne)