Probably not much. Some sanctions from the UN perhaps, because Kim has managed to throw his defiance in the face of every major power of the civilized world, but not much more.

Kim's military is not in the shape to do anything with the bomb, and the weapon is rather wimpy. Don't look for many aggressive maneuvers.

The problem is now political opinion in China, which got snubbed by the Koreans, and public opinion in Japan. Japan may decide to arm themselves over this, which would sned all of East Asia into a tizzy. That's the wild card in this situation, that and how China responds at the UN.