https://www.ozervnews.com

Two snakes are slithering across the ground side by side, suddenly snake A stops and asks snake B are we the type of snake that squeezes our prey to death or are we the type that poisons our prey to death, snake B answers why do you ask, snake A I've just bitten my lip.......

T1 Terry

Well, seriously, if you were a Snake A type, you would rationally have to expect that you were impervious to your own poison. Otherwise you couldn't eat whatever it was that you caught and killed.

Do snakes have lips?