Trust me. It's not really ruined. You just don't know how to undo what she did 'cause you don't know what she did.
My granddaughter used to be able to totally change my computer in two seconds flat, just as soon as she got on my lap at the keyboard....and it took me
forever to get it figured out.
Persevere.
If that fails,
then take it to someone. Just don't give up on it.