I developed drug induced parkinsonism after 28 months of taking flunarizine for migraine. it has been 12 months since i stopped taking flunarizine yet the parkinsonism remains. should i be worried about developing actual parkinson's disease?

I would expect the parkinsonian side effects to resolve after the causative medication is out of your system and true Parkinson's disease would not follow. If you still have concerns, consult a neurologist for evaluation and advice.

Flunarizine is a calcium channel blocker, not available in the USA due to its risks, one of which you have acquired. There is no reason to expect true Parkinsonism on top of your drug-induced symptoms, but the latter needs ongoing neurological attention. Several safer and more effective anti-migraine drugs are available.