Is scarring at the injection site common?

It is not common to develop scars with injections. If the injector used a large needle / cannula and depending on administration of the product you may have a mark left on the skin. Schedule a follow up with your injector so he/ she can determine if this is due to the treatment and decipher steps going forward. You can also assess before and after photos. All the Best. 

Scarring at the site of injection is extremely rare.  I have never seen it and it has never happened to any of my patients.  There may be other causes for this including superficial lumps and bumps from filler injection, that should be assessed by a cosmetic dermatologist or plastic surgeon.  Best, Dr. Emer.

It is not common to see what you describe.  It may be that the restylane is wearing off in that area, or you may have some dermal atrophy or scarring from the injections.  You should not worry for now, as restylane can last for several more months and this may improve as it goes away.  If it continues to worsen, visit with your injector to have it evaluated.