Very Unhappy With Rib Cartilage Harvest Scar- Options?

There are many options for revising the scar and improving the appearance so there is no reason to be upset about it.  Talk to your surgeon about surgically revising the scar to minimize the depression.  Redness/purpleness of the scar will fade over time and can be improved with lasers.  Hypertrophied scars can also be improved with lasers or steroid injections.

Your description of the scar is that of a classic indented nature. In most cases, the scar is somewhat wide as well as depressed. In that case, an open scar excision with reclosure will provide good improvement. If the scar is not wide and is only indented, then fat injections can provide the needed volume for scar elevation. Although you have not posted any pictures, it is more likely than not that an open scar revision is needed. That should be able to be performed in an office setting under local anesthesia if desired.

Yes scar revision, fat grafts can be used to correct this area. But you did not post a photo of the defect so very hard to advise. Seek in person consults.