Uy, I feel you! Yan yung chloasma or melasma na nangyari sa maraming kami after pregnancy, the hormones talaga ang culprit, lalo na sa areas na exposed sa sun. A few of us tried Mama's Choice Face Serum kasi it's pregnancy-safe and breastfeeding-safe (na importante pa rin if breastfeeding ka), and some swear it helped lighten the tone over time, pero honestly two years in, best approach is pa-check mo na sa derma para makita nila kung ano exactly ang skin type mo and recommend the right lightening treatment para sa cleavage area, kasi yan talaga ang specialty nila. Good luck, mumsh!