They can be helped with the use of fillers. For appropriate circumstances, an orbital rim implant can also be very helpful in these situations. My advice however, is to first heal from your orthognathic jaw surgery. Particularly if they advance the maxilla, this can have an effect on the dark circle and even the lower eyelid position. For this reason, see what you need after this big surgery. The recommendation for the genioplasty seems very appropriate.