'DWTS' Iraq War Vet Noah Galloway -- Incoming! Foot Takes Out Tooth

"Dancing With The Stars" contestant Noah Galloway was hit by friendly fire while rehearsing with partner Sharna Burgess ... and it's brutal and bloody.

When you consider what the former U.S. Army soldier's been through -- he lost both an arm and leg in the Iraq War -- it's gonna take a lot more than a busted tooth to rattle this vet.

It's hard to watch ... while practicing their routine Sharna kicks him in the face and you hear a tooth hit the floor like it's tap dancing.

Yet Noah -- a total pro -- only has three little words to say about it ... "No Big Deal."