Acne is easily recognised by the appearance of the spots and by their distribution on the face, neck, chest or back. However, there are several varieties of acne and your doctor will be able to tell you whi If you have acne but have had no success with over-the-counter products then it is probably time for you to visit your doctor. In general, most treatments take two to four months to produce their maximum effect. ch type you have after examining your skin. The most common type is ‘acne vulgaris’.