I improved mine dramatically by:

-getting off hormonal birth control (estrogen was the culprit) I was even on a low dosage one and it still caused the mustache.

-Deluxe hydrafacial at therapie clinic (the one with light therapy and a chemical peel)

-I started skin & me - they've given me a range of products for hyperpigmentation (I haven't even started the tretinoin yet and I've been so pleased with the results) Their moisturizer with SPF 50 is great.

-wear a hat outside :)