Acne is a whirlwind of horribleness & when it (eventually) leaves a whole load of skin damage can remain. Often, we're left with indentations & marks as evidence of our struggle.
The red marks are PIE (which stands for Post Inflammatory Erythema).
The brown marks are PIH (which is the very similar sounding Post Inflammatory Hyperpigmentation).
The indentations left behind in the skin are atrophic scars. All are treatable but lets talk today about PIE vs PIH.
PIE results from the damage to the small blood vessels near the surface of the skin . PIH results from your skins inflammatory response causing pigment cells to produce more pigment in the skin. Chances are if you've had moderate or worse acne you'll have both.
PIE is difficult to treat at home. The go to derm treatment is radio frequency, laser or Intense Pulsed Light which obs you won't have at home (unless you're a bond villain). There's anecdotal evidence supporting a combination of silicone sheets, vitamin C & niacinamide to reduce the appearance of PIE which all point to increasing the hydration of the skin - (you might want to look at Dermatix gel/Clenascar C gel if you want further reading). The principle is simply 'hydrate and seal in the water' but the clinically evidence is lacking at how effective this is.
PIH is easier. To treat PIH you need to inhibit the enzymes which cause skin pigmentation & increase cell turnover rate so the spots fade faster. This can be achieved at home with our old friends the skin acids or retinols (to increase skin turnover),#niacinamide(to help the skin repair) and a melanin inhibitor (#hydroquinone,#azelaicacid,#vitaminC, licorice or a combination).
Its a bit of a plug, but our 2% BHA exfoliating serum has licorice & niacinamide & our skin repair serum has 5% niacinamide among lots of other skin healing goodies but there is lots of choice out there - just focus on hydration and repair and don't go acid crazy - this can cause more trauma and more PIE/PIH.