A brief aside before we get started: I'm not here to freak you out. I only want to help others avoid the anguish I went through of assuming something was safe, and finding out later that this assumption was not entirely true.
Acne. What a sinister word. As if dealing with active breakouts weren't enough, there's the scarring, and the more traumatizing the breakout, the worse the scarring. Sure, that makes sense, but it's still cruel.