I got clarification from the breeder. It happened during a shed cycle, but was actually a scrape injury against the PVC divider in a divided tub (which has now been fixed). There was apparently a sharp edge on the divider that she rubbed against causing the scrape on her back seen below. The top three pictures are before the most recent shed. The bottom two pictures are after last night's shed. It appears to be healing nicely. Is there a chance of it healing completely?

Pre-yesterday's shed:




Post-yesterday's shed: