After receiving a couple of light cross-checks from Lindholm, Hertl was merely fed up and gave Lindholm a tap to the chops. Regardless of the severity of the blow, we know that George Parros and Player Safety don't have much patience for plays like this:
Simply, you can't use your stick like that, regardless of circumstance. Arizona forward Nick Ritchie received a one-game suspension for something similar, so expect something similar for Hertl, but perhaps his absence of priors will lighten the sentence.