How to fade reddish-brownish acne hyperpigmentation on asian skin? i'm already using 0.025% tretinoin for a while now but no significant results

Hard problem: With asian skin, you have more pigment than caucasians and a higher tendency to get hyperpigmentation from almost anything including acne. Tretinoin is a good first step. You could try adding very mild (2%) hydroquinone, after the tretinoin has soaked in, but beware that you might get more irritation and that could lead to increased hyperpigmentation so don't continue using it. Sunscreen ALWAYS