To be honest, the main arbiter of what happens now will be China. China is the local large power, with ambitions to be the local super-power which it will be by default if the Americans can only be persuaded that setting up more of a presence in the neighbourhood is a waste of money. North Korea, which was long kept as a sort of pet of many Chinese administrations as it was vaguely Communist as long as you didn't look too hard, has just done the pet equivalent of crapping on the carpet after being repeatedly told not to.
North Korea isn't a Communist state. Communist states strictly separate the military from the political, and make sure the military is subordinate. Communist states also don't have much trouble retaining power in the ruling group when the original boss-man dies or is deposed, but this is a problem in North Korea. The best political model for North Korea is a feudal Royal one, where an usurper has taken power a while ago and only now are his descendents approaching a steady state of power.
The net political effect in NK now is that everything is unstable. The new king isn't secure; his barons who control the armed forces are restless and uncertain as to how much they think of the new king but nobody wants to break ranks and rebel in case everyone else attacks the rebel to cement their reputation as loyal followers of the king. North Korea right now is a Game of Thrones in a modern world.
This is what the nuclear test was all about: this was partly a show of strength and partly a provocation, so the new king can demonstrate to his barons that the entire world is out to get them, so unity is the only option. Only problem here is, the barons ain't completely daft and probably don't buy it, but as the only real alternative is inviting in China and spending one's retirement in a cell somewhere, they ain't complaining.
Like I said before, China is the arbiter here. If the NK leadership has any brains at all, this will be the last nuclear test (and the last ballistic missile test) for a very, very long time. If they carry on raising the pressure, they're going to get invaded by China simply to get rid of America's main excuse for being in that area, and also for international brownie points for removing a known mad dictator from power. The only thing is, I have grave doubts as to the intelligence and indeed the sanity of the current NK leadership; I am not at all certain that they know just how close to an invasion they are pushing China.