Are Repeated Microdermabrasion Sessions an Effective Method of Removing PIH Caused by Acne?

Melasma and postinflammatory hyperpigmentation are conditions that can resist all treatments and can even worsen as a result of some of the treatments designed to make it better.  Hydroquinones can help lighten the dark skin by blocking the pathway in the cells that make the pigment. To expedite this slow process, some doctors exfoliate by doing microdermabrasion, chemical peels and even Fraxel Dual laser.  Before a treatment plan is decided, it is helpful to exam the darker skin pigment with a Wood's light which can help discern whether the pigment is superficial and amenable to improvement with medicated creams, such as hydroquinone, or if it needs a deeper treatment such as the Fraxel after preconditioning with hydroquinone and/or the newer product, Elure, which has been shown to have a quick action of onset in lightening some patients' hyperpigmentation. Elure uses an enzyme found in nature, in a fungus growing on trees that causes lightening of the bark. Rather than taking weeks to limit the production of new pigment granules which won't show up in new cells for 45 days or so, as in the case with hydroquinones, the Elure can lighten some skin hyperpigmentation in much less time.  There is less irritation with this product than is found in some hydroquinones and this is important because the irritation in some products, including Retin A, can cause more pigmentation!

Brown skin, Asian skin, East Indian skin is prone to hyperpigmentation.
Before you spend $$ on peels or IPL, microdermabrasion, or expensive medical grade chemical peels, try these topicals.
This is called post-inflammatory hyperpigmentation (PIH). 
I recommend Melarase AM and Melarase PM creams from Kare Skin as well as a broad spectrum sunblock like Spectrase. Bothe are from Kare Skin. Scler-x post inflammatory hyperigmentation relief complex is a great supplement to take as well. See link below. 
Spectrase is a wide spectrum sunblock SPF 50+that is also recommended to prevent ongoing inflammation. 

My first-line approach to PIH, specially in olive complexions is creams: combination retinoic acid & 4% Hydrroquinone ; together with relgious use of sunscreens. Procedural intervention is resorted to, only after several weeks. Either microdermabrasion or fractional laser can be used . One has to be very conservative with the settings used, to avoid worsening of the pigmentation.

I believe the best treatment for post inflammatory hyperpigmentation is using microdermabrasion combined with both prescription strength hydroquinone (4%) as well as prescription-only tretinoin cream. These two creams can either be used separately or as part of the Obagi NuDerm system for greater penetration. Laser treatments can be risky as they may cause inflammation that leads to more hyperpigmentation, especially in someone like  you with olive-brown skin color. A chemical peel beginning with a mild strength acid and then gradually increasing the strength as necessary would be my next choice if the topical regimen with microdermabrasion was not working.