A while ago, I watched a video essay analyzing the number of times female superheroes get punched in Marvel movies. There's an understandable cultural taboo against punching women, but in the specific context of an action film where a character's strength is measured in their ability to both give and take blows against equally-matched opponents, it has the net effect of making female characters feel less powerful. Marvel's women are very rarely hit, and when they are, they tend to get knocked out instantly, which gives the impression that women in this universe are just fundamentally weaker than men (or at least that they have somewhat unsporting plot armor). 

For this story, please know that Frankenstein can absolutely take more than one hit--she's built like a tank, and the punch probably hurt Jekyll's hand a lot more than it hurt her face. The only characters who could do serious damage would be the Creature (obviously) or possibly Jasper, who probably isn't very good at punching but is Farm Strong and could absolutely murder an overhead press should he ever have the opportunity to perform one.