It is depend on individual cases
This is Dr. Chintan Solanki here.
It's good that you have stopped cocaine.
Cocaine cause significant cardiac disturbance through sympathetic stimulation and affecting myocardial(heart muscles) tissues metabolism
.Sp it can cause any type of arrhythmia
and PVC is one of them.
These arrhythmia would be permanent or not depends upon many factors.
Use of cocaine in terms of quantity and duration.
Person's nutritional and physical and cardiac status before, during and after use of cocaine.
Severity of cocaine withdrawal and treatment taken for the same as well as treatment taken for arrhythmia.
ECG,TMT and other cardiac evaluation should be done by cardiologist if cardiac toxicity is there.
If you can provide me above details with reports I can tell you specifically in your case it would be permanent or not.
hope you have found the clue from my answer for your next step.
Thanks & Regards.