Restylane is a hyaluronic product that I have been using in my practice since 2003. You should expect improvements immediately but the filler can be a little firm for up to 2 weeks. This may mean that you can actually feel the product under the skin, particularly when used around the lips and corners of the mouth. Great results take time!
Most HA products like Restylane are to some degree hydrophilic meaning they soak up water and expand. This effect is slightly less with Restylane than Perlane. I suspect you will reach your end result in about a week after your procedure. By this time, the local swelling of the tissues from the limited needle trauma has dissipated, and your results should be seen.
Thanks for the question!
Dr. Hobgood