Hi how can be melasma spots on a face be treated thanks?

There are many : options available including chemical peels and lasers. See a dermatologist for treatment options but most important is using a lightener and suncsreen the higher the better and with Zinc or Avobenzone to cover UVA too

Melasma?: Melasma or changes in facial coloring is related to hormonal changes. Since you are post-menopausal age, are you taking hormone or estrogen replacement therapy? Are the changes recent or long term? Talk with your GYN or dermatologist about options such as creams or laser therapy. If taking hormonal therapy, the changes may be chronic as long as you take estrogen/progesterone.