I frequently have a new client come in who is concerned about what they call "acne scarring" and when I look closely at their skin, I can see no scar tissue but rather Postinflammatory Hyperpigmentation (PIH) which is often a result of acne - but is not a scar, by definition. I think it is really important to identify what the actual skin condition is that you are trying to treat as each may require a different approach in treatment.
Estheticians usually see two kinds of PIH. Lesions appearing red to light brown are generally epidermal hypermelanosis where a darker grey to brown often indicates a deeper condition known as dermal melanosis.
So here is the simple prescription for your home ritual: Peel, Heal, Prevent, and Protect.
Peeling and exfoliation plays a major role in both clinical treatment and home care, this step is critical in removing dead, stained surface cells quickly.
Apply a topical antioxidant. I strongly recommend L- Ascorbic Acid (Vitamin C) - not only is it incredibly healing, but is a powerful, multi-tasking anti-inflammitory that will, over time, significantly brighten the skin's appearance.
Slow down or "inhibit" Tyrosinase, the enzyme that catalyzes the oxidation of the amino acid tyrosine and is involved in the formation of melanin. There are several natural ingredients to look for in brightening products that act as Tyrosinase Inhibitors such as Licorice Extract, Arbutin (Bearberry Extract), and Lemon Peel to name a few. Check your labels for these ingredients if you are looking for natural/non-toxic solutions.
Finally, although it should go without saying at this point, it would be a failure not to mention...SPF. You can't even think about treating ANY type of pigmentation without the diligent use of sun protection. I hate to say "it's just common sense" because well, apparently, it's not.
Oh, and by the way, a hat wouldn't be a bad idea either, nudge, nudge.