UFC's Devin Clark Talks Gruesome Jaw Injury, Pain Was A 7 Or 8 Out Of 10

Devin Clark sustained one of the most gruesome injuries you'll ever see in a combat sports event ... and now the UFC fighter is answering the question -- how much it did hurt?!?

"It was probably a 7 or 8 after the fight. You fight the fight. He got his hand raised. Then that adrenaline starts coming, and it comes down quick. And, by the time I'm leaving the cage, I'm like, 'Okay, that hurts,'" Clark tells TMZ Sports.

If you didn't see the injury (lucky you) ... it was incredibly gross. Devin was fighting fellow light heavyweight fighter Ion Cutelaba at UFC Fight Night Saturday afternoon.

31-year-old Clark ate a heavy knee in the 2nd round ... a shot so hard it literally displaced Clark's teeth.

It was bothering him so much during the fight, he went back to his corner before the 3rd round, and told his team something was wrong with his teeth.

The ringside doctor even examined Clark at one point ... but somehow let him continue.

And, continue he did, despite the pain.

After the fight, Clark went to the hospital and they patched him up. On Tuesday, he plans to see his dentist ... and the road to recovery won't be easy or quick.