Unable to undo Thumbs up/down

[seiffs]

Why can't I undo thumbs up/down? IMHO it's a UX fail 😞

Imagine you don't like the song it's playing so you want to click the Next song button and you miss the button and you click just a few pixels next to it to Thumbs up button! And than you realize you can't even undo it! 
Frankly I don't know what thumbs up/down do, there's no information about what it does in the tooltip. But I imagine I'll be hearing more of the song that I wanted to skip.