I'd get an upholstery repair profession to look at it. I've seen them work wonders. I would recommend calling your dealer for a reference. These guys usually come by the dealerships a few days a week to do repairs for their used car inventory (and any mishaps that occur with new or service vehicles).
If you can get the cover off without tearing it up you might be able to have the leater panel replaced. We have big leather repair place in Houston that can repair anything leather. Found it after my dog ate a tennis ball sized hole in the sleeve of her shearling coat. They had leather to match and made the other sleeve match. You would have never known. They also fixed furniture so automotive wouldn't have been much of a stretch. The places that do he repairs are only interested in having it last through a 30 day used car warranty. If it is where there will be much stress, even worse. A used seat might be an option. For a lot of folk the back seat doesn't get much use (they use cheap motels).
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