Johnny Manziel: Who Needs A Mouthpiece? ... I GOT A NEW GRILL

There's one shiny part of Johnny Manziel's nightmare spring ... his face ... 'cause the Hollywood bad boy has officially followed the lead of his old teammate Von Miller ... and copped a custom grill.

We noticed the ice when we got Johnny leaving Warwick nightclub in Hollywood ... sporting a twinkle in his smile we hadn't seen before.

That caused us to do a little digging ... and it turns out Manziel hit up celebrity grillsmith Johnny Dang and commissioned some custom swag for his chompers.

Dang was mum on how much Manziel's 18 karat white gold, diamond encrusted creation actually cost ... but said similar pieces he's done in the past would set you back around $20k.

Keep swaggin' Johnny ... it's your job now.