While often done, injection of fillers into the the tear troughs is not without risk. It is off label and several side effects or complications can occur: irregularities, swelling, bruising and the product showing through the skin or reflecting the light to look blue (called Tyndall affect). Blockage of a small blood vessel with the material can lead to loss of skin and even blindness.
The more accepted treatment for tear troughs is a lower lid blepharoplasty with movement of protruding fat of the lower lids into the tear trough. This is a lower eyelid blepharoplasty with fat transposition. This can be done through the inside of the eyelid, transconjunctival. I have attached a link to some photos this procedure.