As far as I know, a bite like Lee's (which might only not look so bad because of the game's art style) or even a scratch has never been addressed in The Walking Dead universe. Although, I'm pretty sure a bite is a bite. The saliva transferred by a walker when they bite a human makes the virus 100% lethal, according to the rules of Kirkman's world.
I have slim hopes of Lee surviving. I'm pretty sure he's a goner, but obviously I can't say for sure.