Is 8% Hydroquinone Safe to Use on Both Full Legs for a Long Period of Time?

I have extensive hyperpigmented scarring on both of my legs from years of shaving (my skin is super sensitive). I have used 4% hydroquinone for the last six months but it has not lessened the patchiness of the skin. I am considering using 8% hydroquinone. If I use it on the large surface area of the legs for a few months will it be harmful? Is it safe to use for such a long time on such a large area?