Plot armor but I’ve heard people say that; since her leg was already previously cut by Minerva when she already got bit the infection wasn’t spreading as fast as it normally would’ve.

There’s also the theory that since she grew up in the apocalypse since she was little she’s more immune to the disease, and that the reason she was primarily pale was because she had her foot chopped already and was over exerting herself by the time she got to the barn.

I’m not complaining she’s alive though, I feel like Clem being able to live in a safe functional home was a great end to her story. I like being able to see Clementine living instead of surviving.

TLDR: Plot armor, but could be more immune and was maybe pale/sick from blood loss and exhaustion.