I got it this year, I don't really remember when, I think it was from a scientist, but I don't know how to make it's skin back to normal, help please?

You can simply claim it in the beta wardrobe (here) and choose the 'None' option to get your normal skin back. C:

Oh, and then I can put it back on if I want to? Thats so cool! Thank you ♥

Yep! You can do that for any skin you get now~ You're most welcome.