Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Acne ?
    ### Response:
    Acne is a common skin disease that causes pimples. Pimples form when hair follicles under your skin clog up. Most pimples form on the face, neck, back, chest, and shoulders. Anyone can get acne, but it is common in teenagers and young adults. It is not serious, but it can cause scars.
    