No. No spontaneous "cures" of parkinsons disease occur. The disease however may fail to progress for long periods of time but once initiated, never goes away.
Yes. Parkinson disease is a degenerative disorder of the nervous system that affects cells in the brain associated with movement. Once the cells are lost they cannot be regenerated and you will see a decline in motor function. Medications, surgery and other management can provide relief and sometimes improve symptoms, but the cells cannot be replaced and the disease cannot be fully cured.