eh, i kind of hope she ends up with her original (well, original dark spirit king blessed) skin color. Maybe just change her hair to silver or grey or something instead of black? to show having both light & dark blessings?
I dunno, that's kind of like becoming rich suddenly (lottery). Its very easy to get drowned in paranoia about "is this person just talking to me/being nice to me 'cause they want my money?!", which for her is going to be "is this person being nice to me cause i'm pale now?". It's easily reinforced by lots of people being nice to her suddenly... unfortunately from the timing, that could just be because she did a great deed for the kingdom and didn't kill anyone when doing it (soldier and other noble reactions pre-blessing). She's been robbed of having any real time of living with how people would've treated her after just that event. If this blessing event had happened a few weeks or months later, the MC would have a better foundation for being able to tell the difference in people's more positive reactions. Now, it's all being pushed into "oh, so its because i just look normal now?! FU!".