A WILD CATALINA APPEARS!
It is of no importance whatsoever to the plot, but in my mind, that bartender has gotten into fights with bandits, and that scar on her left arm is from blocking a blade with her left arm, which was immediately followed by punching out the bandit with her right arm.
I have nothing so specific regarding the scars on her scalp and eyebrow, and that missing part of her left ear. Those could just be from pub brawls.
Anyway, don't start trouble in her pub.
Note: That "technically" is nothing sinister. She's just referring to the alcohol itself.