@new.centenarian: Post-inflammatory erythema (PIE) causes red acne marks from vascular damage, while post-inflammatory hyperpigmentation (PIH) shows brown or gray marks from melanin. Knowing the difference helps target treatments correctly and avoid deepening marks, especially for melanin-rich skin. #postinflammatoryerythema #pie #postinflammatoryhyperpigmentation #acnetreatment #skincareeducation