I'm not so sure. It certainly shook Hezbollah and no doubt some of the dead or seriously injured held sufficiently important jobs within the organization to cause problems.
On the other hand you now have a few thousand people who suffered unpleasant but not debilitating injuries who are now sadder, wiser, and very very pissed off. My impression is that many of those attacked could have been middle managers or mid-ranking officers. They're now veterans of a traumatizing national event, which will probably increase Hezbollah's standing among the general populace.
(The notion of Hezbollah as a mob of ak-47 wielding foot soldiers is a stereotype from movies and TV that seems to have taken root among many HN readers.)