How long does dystonia usually last?

Not simple: Depends on type of dystopia, underlying disease causing dystopia. Like dystnia from carpal tunnel is likely to go away when cts is treated successfully. Some hereditary diseases like dystnia musculorum is a life long problem.

Dystonia: If you are asking about dystonia as a side effect of taking medication, the dystonia will last as long as you are taking the medication. If this is a side effect, the dystonia can be relieved by using benedryl. Speak to your doctor for help with this.