No easy answers. You need to rotoscope/ mask it out using Rotobrush or conventional masks and replace the background.
For a quick and dirty solution, maybe you can isolate the overexposed regions with a luma key and fill some with some gradient or noise.
If you replace the entire background and roto the talent as Mylenium suggested, I recommend combining mocha with Refine Edge, as I show in chapter 4 of this tutorial:
Also, I would then do the roto of the hair and the remaining part separately, such that you can tweak the settings of the refine edge tool for the hair independently.
I like the idea of pulling a key based on the luminance, but you might even be able to knock it back with Curves or something similar since it's SO much brighter than the rest of the shot.