Acne is the worst. You don’t know when a breakout is going to hit the surface, but it almost always happens right before you have an important social event coming up. The factors leading to this skin nuisance are many, and they may be both internal and external. Most of the time, oily skin seems to be the culprit. When excess sebum (the skin’s natural oil) is produced on your skin, it clogs your pores and causes acne. Environmental pollution can also be equally responsible.