I've been using retin-a gel(0.01%)for pigmentation and acne scarring. How long before I see results?

I am of Indian decent. The pigmentation above my lip only appeared when I was around 11 years. I've tried many creams to no avail. I recently had skin peels to help with the pigmentation/acne scarring, this has helped improve the appearance slightly, but it is still noticeable. Would 0.01% suffice? Or should I go for a higher percentage? Are there any alternatives? Many thanks.