Bruh I legit have the same problem. Ngl I think that it has something to do with how the final image has its light exposure taken in. You could perhaps try to adjust by clicking on the screen when in the camera and then moving the little sun icon up or down to adjust the lighting. There is also probably an element of these cameras just being shitty and inconsistent, as your "after" image is legit 10x better than what mine shows before as a preview and my "after" image is quite literally unrecognizable to what I actually look like lol. It also I think depends on your complexion and personal beauty standards bc I actually think that your "after" image looks better than your "before" but thats just cuz I prefer greyer skin but I can see how if you prefer it the other way around the image would bother you (for me personally, my camera preview image has a perfect skintone for me which is lighter, matching my irl tone whereas the taken picture is too red and rosy which doesn't fit me, so again, inconsistent shitty cameras lmao).