“Will cause hyperpigmentation”

I had 4 fraxel treatments for melasma spaced 1 month apart. It has been 7 weeks since my last fraxel treatment and I have been left with more pigment spreading around the original area and extensive hyperpigmentation around other areas. The person treating me says to wait a few more months and it should lighten. I do not see how this can possibly happen as the original pigment hasn't gotten better since my initial treatment over 5 months ago so how can he suggest that the hyperpigmentation will automatically go away on its own.