The inflammation caused by acne leaves wounds in the skin. As the wounds heal, collagen is left behind that forms acne scars and makes skin uneven. Acne can also cause skin discoloration when an inflamed pimple causes over-production of pigment in the skin. This discoloration, called post-inflammatory hyperpigmentation (PIH), usually fades with time. Learn more here: https://masterpieceskinrestoration.com/blog/acne-scar-treatment/