'Traitors' Winner Rob Rausch Banged Up Bad After Bike Slams Into Dog

Not a great look for "The Traitors" star Rob Rausch -- literally -- 'cause he’s on social media showing off some gnarly injuries after a brutal bike crash.

Check it out ... the reality star’s face was covered in cuts and gashes as he explained a dog ran out in front of him mid-ride -- sending him flying over the handlebars, knocking him out cold and leaving him with a concussion. Ouch.

Rob says it all went down while he was teaching a friend how to ride -- and had lent out his helmet -- which explains why he took the full hit.

Before fans could panic, Rob reassured everyone he’s gonna be just fine and on the mend.