Demi Lovato Knocks Out Trainer's Tooth & the Aftermath Looks Brutal

Demi Lovato

Mama said knock you out -- or at least that tooth! (Yikes.) Folks might want to think twice about coming for this celebrity as Demi Lovato knocked out someone's tooth while sparring. And it's safe to say this guy might want to invest in a stronger mouthpiece ... and make an appointment with his dentist soon.