Everybody responds differently to Restylane eyelid treatments.
Restylane works by attracting fluid to the area where it is injected. Additionally, eyes swell very easily. However, the amount of swelling, and how long it lasts is related to your tendency to swell. Do you're eyelids swell a lot in the morning? Do you have allergies? Does eating salty foods, make your eyes swell? All of these things are hints that your eyelids may swell more with Restylane than the average person.
My advice is that the first time you get a treatment, do it at a time...