My guess is that you're talking about hemifacial microsomia. The surgical correction usually involves orthognathic surgery, although some cases can be treated with distraction osteogenesis (DO). The orthognathic surgery involves cutting the mandible and maxilla free from the skull base and repositioning them. More severe cases require additional osteotomies or alloplastic augmentation to correct size discrepancies in the facial bones.
Sometimes the ear is deformed or even missing on the hypoplastic side of the face. This is probably the most challenging part to reconstruct because it is such a 3-dimensional structure which projects out from the face. I would probably just go with osseointegrated implants with an auricular prosthesis because the ones I've seen look much better than ears reconstructed with rib cartilage, etc.
I would definately see an oral surgeon first for a proper orthognathic examination, because this is the biggest portion of the treatment. He would also be the one to place implants for the ear if needed. If you go to a plastic surgeon, I would definately find one who has done a craniofacial fellowship. They are generally the only plastic surgeons who have really had any experience with orthognathic surgery, but it's funny how they still consult our OMFS faculty routinely for treatment plans.