Blueish Tint/bruising from Restylane on Cheeks

Of course all the answers below are all excellent and I have only a few comments"
Did the Restylane achieve your goals?

If the answer is yes then there are a couple of answers. The restylane may be too superficial but then your options are to remove it and suffer the condition which originally occured; I presume hollows below the eyes
However, it is also likely affected by the thin quality of your skin which cannot be reversed. It is similar to saying why do you have blue veins on the back of your hand? If your skin is thin you will see nearly anything placed beneath the surface.
How do you hide this? Well I would advise you to use camouflage make-up. Although this may seem paradoxical and you may be asking why you had the restylane injected in the first place. Well if the Restylane filled the groove or trough or fold then it achieved a significant goal and the trade-off is the color. I like analogies so I will use one. IF you have a dent in your car they need to pull the dent out or fill it with bondo. That achieves correction in form but not necessarily in color or surface texture. The car will need painting and you may require make-up. That may be overly simplified but it makes a point.

If the Restylane did not achieve your goals

Contemplate having it removed by using hylauronidase or having it expressed with a needle as described below.

I hope the helps!

The most likely cause is a superficial injection of Restylane producing the blueish hue. It can also be acute swelling that gives this temporary coloration.
You may just want to wait it out and let the hyaluronic acid and swelling dissipate, hopefully that will solve the problem.
Always make sure you know exactly what is being injected. Many of our patients have received silicone injections without being specifically told what the substance is. The trouble in those cases starts years later when the patient notices chronic swelling or migration of filler.