Blythe Simply Peppermint scalp discolouration

I bought this scalp and it has arrived very discoloured on top- it has a rather nasty browny yellowy hue in places. These photos were taken in the dim light of my bedroom on my mobile camera, and the colour difference is even more noticeable in daylight.

Does anyone have any ideas how I can attempt to remedy or make the colour look a little less ghastly?

Done