1. A system to provide feedback control for spinal cord stimulation, the system comprising: a lead adapted to be implanted within an epidural space of a dorsal column of a patient's spine; a pulse generator (PG) electrically coupled to the lead, the PG configured to deliver spinal cord stimulation (SCS) therapy; sensing circuitry configured to sense an evoked compound action potential (ECAP) response that propagates along the neural pathway; and a processor programmed to operation, in response to instructions stored on a non-transient computer-readable medium, to: obtain a baseline ECAP response when the lead and spinal cord tissue properties are in baseline states; analyze ECAP responses relative to the baseline ECAP response to obtain an ECAP feedback difference indicative of a change in at least one of the baseline state of the lead and the baseline state of the spinal cord tissue properties; and adjust an SCS therapy based on the ECAP feedback difference, wherein the SCS therapy creates current flux density (CFD) at nerve fibers within a target tissue site along the neural pathway, and wherein the processor is configured to utilize the ECAP feedback difference to adjust the SCS therapy to maintain a select CFD level at the target tissue site.