A quick primer on light therapy: red light is known to promote circulation and reduce inflammation while blue light targets acne-causing bacteria and makes oil glads produce less sebum. What this mask helped me most with was preventing new breakouts from forming on top of the cluster already invading my chin. It stopped what was previously a never-ending cycle of acne.
Acne (acne vulgaris, common acne) is a disease of the hair follicles of the face, chest, and back that affects almost all teenagers during puberty -- the only exception being members of a few primitive Neolithic tribes living in isolation. It is not caused by bacteria, although bacteria play a role in its development. It is not unusual for some women to develop acne in their mid- to late-20s.