If the darkness is due to "shadowing" associated with lower eyelid fat pad bulging, use of fillers can be helpful.
The skin is very thin as is muscle there, so exceesive filling may cause lumpiness. Many are choosing fat grafting (from tummy or thigh areas) to be placed under the muscle of the lower lid to provide more fullness. Often better to remove excess fat pad. Lasers may help if pigmt.