Dystonia can be a separate condition or it can be part of PD.
PD meds can help. You can get dystonia when your meds wear off. You can also get dyskinesic dystonia from your meds.

I get dystonic spasms in my feet where my big toes curl up and the other toes curl under. I feel my toes starting to curl when it is time for my next dose of sinemet. Then they curl tighter as the sinemet takes effect (dyskinesic dystonia) and then finally release and are good for a couple hours.