that looks like a very bad fungal/mold infection, she needs to be seen by a vet as medication (ie.. Itraconazole, Terbinafine) which may only be available via a vet if required, she should be kept in water containing 100% holtfreters, give her methyline blue baths, formalin baths (consult vet before use)
also do a full water check (which I assume you have done already)