Black screen, please help

[Shanlea]

I got my son a Flytouch 2 and some how were you can dim or bright your screen, he dimmed it all the way and then it shut off on him. Now when its on it all black and you can't see to do anything and we can't see to get back into the setting to brighten it back up. I don't know what to do. Could someone please help. Thank you