If you want to know more about dystonia, Parkinson's or other movement disorders, wemove.org is a great source of info.

The difference between the two is very complicated. It doesn't have to do with which one is "worse."

Dystonia simply signifies sustained involuntary muscle contractions. It includes a variety of disorders, including genetic diseases as well as a secondary version caused by other problems (stroke, tumor, injury, toxins, drug reaction, etc.). Parkinson's is a single disease thought to be caused by a combination of genetics and environmental factors. (Dystonia can be a secondary effect of Parkinson's if Parkisnon's is untreated.)

Dystonia can affect the whole body (generalized dystonia) or may affect one or more individual parts of the body. It can range from a minor annoyance to paralysis to a life threatening condition (not being able to breathe, for instance). The prognosis varies from complete remission to complete debilitation and death, with most people stabilizing long-term, not getting better or worse.