welcome to RP.
i'd take yours one step further and do just a bit of noise reduction. not much, just a bit.
i took a shot at this also. quite a stinker. i found myself adding just about every adjustment layer possible. i didnt end up using all of them, but quite a few. what i really found helped most was a histogram adjustment filter. i also did noise reduction with psp's digital camera noise removal and color balance with smart select to get the white settings and color balance better after all the adjustment layers.
i cleaned up scratches with scratch removal and push. i also did some individual sharpening on things like the eyes. those could still use some hand work, though.
tricky image overall.