Human: I have a lot of acne and I want to find out what causes it. Assistant: 
Acne is caused by bacteria that live on the skin, and when they multiply they can cause inflammation and pus-filled bumps. It's not clear exactly why this happens, but there are some things that may increase your risk of developing acne. These include using too much oil-based makeup or skincare products, having a family history of acne, being overweight, and having hormonal changes like puberty.