A leather repair service will charge $ 160 to $ 200 to 'weld' the cut on the back, personally I'd just get a leather needle and thread and sew it up, Or some Super Glue and bond it together with a patch underneath IF YOU ARE CAREFUL with the Superglue. Superglue was invented to bond skin in medical emergences and does cowhide very well). Magic marker is forever, forget about that one. You cannot reupholster in leather, it would exceed the cost of a new chair.