Will Under Eye Restylane Injection Be Noticeable when Smiling?

Hello - Yes, Restylane is great for treating the hollowness under the eyes, and shouldn't give you the frozen look that Botox can do. However, if you get Restylane placed into lines that are only present when you smile, then you may be able to see them at rest. Lines that are present in repose are the ones that should be treated with Restylane.

Under eye use of Restylane is becoming more and more popular because it can work so well to reduce an overly depressed under eye "hollow".
Depth of injection is critical. Balance is critical. The physician has to take into account much more than just the hollow area under the eye. The perfect correction will not be noticeable at all and will not show at all when you are smiling or at rest.
Thoroughly vet your injecting physician. There is an art to doing this particular injection correctly and and not every physician has the eye to do it well. Ask to see photos of patients your doctor has treated. This will be one of the best ways to make sure you will get what you are looking for.
Be sure to follow pre-injection directions as certain supplements or medications will make you more susceptible to bruising and/or swelling. Do it a little at a time if your hollows are deep. Incremental depositing of the filler will prevent any over correction and allow you to get an even symmetrical result.

Both Juvederm and Restylane are hyaluronic acids that can fill in hollows. It depends on exactly where the holow is. If it is close to the eyelashes of the lower eyelid, then the filler must be injected above the muscle and this may leave obvious bumps and because it is very difficult to make the filler look homogenous under this very very thin skin. Also, bruising is very possible in this superficial plane.
The tear trough which is lower on the eyelid skin adjacent to the beginning of the top of the cheek, can be filled below the muscle and gives a more natural appearance. It won't freeze your face when you smile because you should not get such a large volume that it interferes with your smile or lumps up. Fillers don't affect the muscle action as Botox does.
This treatment is considered an off-label use by the FDA. Make sure you see an experienced injector in consultation to review your concerns.