Will there be scarring? If so where will the scars be located?

This depends on the incision choice by you and your surgeon.  It is quite possible to have your implants inserted with no visible scars, whatsoever.  Ask your doctor if he is familiar with the intra-oral incision and what he thinks about it.  Ask him if he is aware of the inner lower eyelid incision for cheek implants which results in NO visible scars and any infection is a rarity.  Although ectropion is at risk here.  Ectropion is a condition where your lower lids are pull down or gape.   If you should develop ectropion, further surgery will more than likely be needed to correct it.  Which could lead to more risks and more cost to you, the patient.