Restylane injection for upper eyelids hollowness, safety and cost in LA? (photos)

As I am getting older the hollowness above my upper eyelids is getting worse. I'm looking into getting filler (HA perhaps, No fat transfer) injected in the areas. I would like to get answers to the following questions: 1. To what degree would the filler solve the problem? Is it safe to inject in the upper eyelids? 2. How long does the result typically last? 3. How much filler would I need (1 synrigde per eye? ) 4. How much does this procedure cost in a case like mine? I'm in Los Angeles.