Acne grows in stages. If we allow acne to grow up to the third stage, it may burst and also leave permanent scars. To understand how acne may be stopped to grow up to second or third stage, it is important to know more about the later stages of acne. Blackheads and whiteheads are first stages of acne. In the later stages they break out as papule, pustule, nodule and cyst. Let us find out more about them. What is a papule - a papule is a slightly elevated lesion that is solid. Papules are generally less than 5 mm in diameter. What is a pustule- pustules are filled with pus that contains dead skin cells, white blood cells and bacteria. Pustules are fragile and can easily break. Pustules are dome shaped and contain a hair in the center when they form over a sebaceous hair follicle. Pustules can progress to cyst. What is a Nodule- a nodule is an inflamed lesion that extends to deeper layers of skin. A nodule looks like a papule and is dome shaped like a papule. Nodules can cause scarring as they damage the inner tissues of the skin. What is a cyst- a cyst is severe form of acne that is filled with bacteria, white blood cells and dead skin. Cysts can be very painful and extend inside the skin damaging the skin tissue. Any acne that damages the skin tissue deep inside can form scars. For the above forms of acne, it is always better that you consult a dermatologist and get treated not only to cure the acne quickly but also stop scarring as much as possible. Please remember that acne may get healed but scars always remain for the lifetime. It is better to get cured at an early stage to prevent inflammation and stop scarring. This article is only for informative purposes. This article is not intended to be a medical advise and it is not a substitute for professional medical advice. Please consult your doctor for your medical concerns. Please follow any tip given in this article only after consulting your doctor. The author is not liable for any outcome or damage resulting from information obtained from this article.