The only thing that has worked for me is consistent use of Vitamin C serum over time. I prefer OST C20, but I know some people don't care for the stickiness or for the need to keep it in the fridge so it doesn't oxidize.
Mine clear up well with a strict Good Genes regimen (every 2-3 days), cosrx skin returning a-sol 2x a day, and vitamin c (I am using the drunk elephant one) every couple of mornings.
I'd get some stuff from The Ordinary: lactic acid (active in Good Genes), arbutin (active in Tidal), and a retinoid. You're already doing a C. There's also hydro-quinone, and PC has some lightening hydroquinone products.
Being consistent with my routine has helped a lot. Curology has helped a lot with mine - my formulation is Tretention, Vitamin C and Niamacide. It may be the combo but I had used Vitamin C in the past with good results too. I had issues finding a serum that didn't oxidize so I eventually gave up and then found Curology.
I'd get some stuff from The Ordinary: lactic acid (active in Good Genes), arbutin (active in Tidal), and a retinoid. You're already doing a C. There's also hydro-quinone, and PC has some lightening hydroquinone products.
Apparently I'm obsessed with The Ordinary, because I found this:
Example regimen for pigmentation issues: AM: Alpha Arbutin 2% + HA, Niacinamide 10% + Zinc 1%, Magnesium Ascorbyl Phosphate Solution 10%; PM: Alpha Arbutin 2% + HA, Azelaic Acid Suspension 10% or Advanced Retinoid 2%
If you go to the link it also gives instructions on order of application.
Thank you so much! I currently do: AM DE bar, c firma, b hydra, bare minerals complexion rescue PM Argan cleansing oil, DE bar, Dennis Gross Ultra Gentle daily peel, Kate Somerville retasphere, Kate somerville nourish
A few days a week I do KS Exfolikate and a hydrating mask.
As I run out of that stuff I plan to replace with stuff from The Ordinary.