Restylane and Juvederm are both hyaluronic acid, just manufactured by different companies (Medicis and Allergan, respectively). Restylane was FDA approved in 2003, Juvederm was FDA approved in 2006. There is no reason why you cannot switch from one to the other. The products may last different amounts of time once injected, however this can also be influenced by the skill / technique of the injector, the locations being treated and variability from patient to patient.
Good luck.
My response to your question/post does not represent formal medical advice or constitute a doctor patient relationship. You should continue to follow-up with your plastic surgeon in order to receive a formal evaluation and maintain your doctor patient relationship.