Several scales exist to grade the severity of acne vulgaris, but no single technique has been universally accepted as the diagnostic standard. Cook's acne grading scale uses photographs to grade severity from 0 to 8 (0 being the least severe and 8 being the most severe). This scale was the first to use a standardized photographic protocol to assess acne severity; since its creation in 1979, the scale has undergone several revisions. The Leeds acne grading technique counts acne lesions on the face, back, and chest and categorizes them as inflammatory or non-inflammatory. Leeds scores range from 0 (least severe) to 10 (most severe) though modified scales have a maximum score of 12. The Pillsbury acne grading scale simply classifies the severity of the acne from grade 1 (least severe) to grade 4 (most severe).
If your acne is severe, painful, or refusing to get lost, you may just be beyond what an over-the-counter treatment can do. Not only can a professional set you up with the really powerful stuff, but also Fitz Patrick explains that “working closely with an aesthetician or dermatologist means you can keep tweaking a routine to make it work best for you.”
Blackheads are a mild form of acne that appear as unsightly, open pores that look darker than the skin surrounding them. They get their dark appearance from a skin pigment called melanin, which oxidizes and turns black when it's exposed to the air. Blackheads aren't caused by dirt, but by sebum (oil) and dead skin cells blocking the pore. If the pore remains open, it becomes a blackhead; if it's completely blocked and closed, it turns into a whitehead.
^ Hay, RJ; Johns, NE; Williams, HC; Bolliger, IW; Dellavalle, RP; Margolis, DJ; Marks, R; Naldi, L; Weinstock, MA; Wulf, SK; Michaud, C; Murray, C; Naghavi, M (October 2013). "The Global Burden of Skin Disease in 2010: An Analysis of the Prevalence and Impact of Skin Conditions". The Journal of Investigative Dermatology. 134 (6): 1527–34. doi:10.1038/jid.2013.446. PMID 24166134.
Pimples are raised red spots with a white center that develop when blocked hair follicles become inflamed or infected with bacteria. Blockages and inflammation that develop deep inside hair follicles produce cystlike lumps beneath the surface of your skin. Other pores in your skin, which are the openings of the sweat glands, aren't usually involved in acne.