What does hand twitching indicate?

Not Sure?: I am not clear on what you mean by hand twitching. If your hand has a tremor while at rest and this is new it should be checked out. If you have a tremor while trying to do something with your hand, an intention tremor, this too should be checked out by your doctor. If your hand seems to spasm after you have been doing something like writing this can be a sign nerve entrapment. See your doctor.

Usually just overuse: Occasional hand twitching is often secondary to fatigue or overuse. If it occurs more often than that it could be a tremor or related to another condition such as carpal tunnel syndrome.