In reply to Sara.
Hi,
Please consult your vet as it certainly sounds like something serious is going on. You need a veterinarian to diagnose if it is a fungal or bacterial infection or a vitamin/mineral deficiency, or a combination of these. Only a veternarian will be able to correctly advise on this once they have examined your tortoise. Hopefully you get a good outcome.
Best of Luck
🙂
Bec