In reply to Stormy.
Hi Stormy,
Thank you for your question. If you are fairly sure that it is not a calcium/vitamin D deficiency it could be a fungal infection. Please find a veterinarian that specialises or treats turtles and they will be able to correctly diagnose and if it is a fungal infection they will be able to prescribe some medication to help.
I hope this helps, good luck.
🙂
Bec