Johnny Manziel Fiancee's Lip 'Hanging Off' After Dog Fight

Johnny Manziel's fiancee, Bre Tiesi, almost had one of her lips torn off by a dog ... but it looks like she's gonna be OK after one of the Kardashians' plastic surgeons worked his magic.

Bre detailed the scary incident on social media -- saying her lip was "legit hanging off" after she tried to break up a canine throwdown involving her two pups.

But the IG model wasn't about to let a random ER doc mess with her kisser ... so she hit up Garth Fisher -- a Beverly Hills surgeon who's worked on Kris Jenner -- and he stitched her up, good as new.

Well, not exactly ... but Bre says she should be scar-free in just a few weeks!

Not like she wouldn't be smokin' hot either way.