Look in a mirror.
Puberty. Always a mistake.
A variety of anaerobes.
Try a good squeeze in front of a mirror. Be sure to clean up; everyone hates zit splatter and remember, with every squeeze you are bacteremic. Hope your mitral valve isn't too bad. I would refer you to a good dermatology text book; this is not a disease that is in my purview, although of great interest to my teenagers.
ICD9 Codes (Soon to be supplanted by ICD10)