This has to do with what type of skin you are born with.
This most likely happens during puberty and when you are growing up.
Stress isn't a main cause of acne but it does have an effect. It can make acne worse. But every time you are stressed doesn't mean that you are destine to get a pimple the next day.
This type of acne can be caused by makeup, sunscreen, and other products. They can clog your pours and cause you to break out with acne.