It is a lot harder to treat acne and pimples in an adult than it is to treat them in a teenager. One of the main reasons that an adult may get acne or pimples is due to a hormonal change or imbalance within the body. If this is the case, then the hormonal problem will have to be treated in order to eliminate the acne or pimples. It is also far more common for adult women to develop acne or pimples than men because women have different hormones than men.
In order to treat adult acne or pimples, the doctor usually prescribes some sort of hormonal therapy with an antibiotic ointment or cream that is rubbed on the acne or pimples. You should consult a doctor if you condition is severe.