A dr said microdermabrasion brings out melasma which i have,yet i've heard they do microdermabrasion to help melasma,i'm confused do i keep doing it.

Melasma + Microderm: Melasma is a common skin issue that can form for many reasons including hormonal changes. It can get worse with exposure to the sun and is a a deep form of hyperpigmentation. I would not recommend microdermabrasian to treat it as that is good for exfoliation of your skin at a very superficial level. To help treat melasma, you need to reach deeper into the skin where the melasma is contained.

Microdermabrasion?: Microdermabrasion can be used for a number of ailments. Hyperpigmentation is one of them, but it depends on your skin type and the extent of the melasma. In general, I suggest that you seek consultation with a board certified plastic surgeon.