How To Cure Pigmentation Of Skin On Vaginal Area?

I bumped into some machinery at work over a year ago painfull and heavy bruising around right bottom cheek and vagina area ended up with a hematoma. Skin is now coloured dark blue and has never gotpigmantation back my Dr says most likely colour will never retain its

original pink I am about 5 stone overweight so If I lost weight would this help.