I would go by the care sheet.
"Seek advise from a veterinarian versed in the special medical needs of amphibians. They will be able to prescribe appropriate antibiotics and treatment regimens for your pet. Often, injectable antibiotics can be used topically, either as a medicated bath or by merely dripping a calculated dosage onto the animal’s back. (Due to their highly permeable skin, amphibians can absorb medication this way.) Commonly-used antibiotics include enrofloxacin (Baytril, Bayer) or amikacin. Your veterinarian will be able to take samples of the site and run testing to determine the antibiotic to best treat the infection"
But if you cant find a vet or this option is not viable to you i would go with:
While professional veterinary advice is recommended, some may not have access to a veterinarian knowledgeable enough about amphibian medicine. In these incidences many keepers will use medications commonly available over the counter for aquarium fish (kanamycin, tetracycline, Maracyn, Maracyn 2, or nitrofurazone). It is imperative to follow the manufacturer’s directions carefully. However, these medications are only beneficial for aquatic animals. For terrestrial or semi-aquatic animals medicated baths may be prepared using these medications in high concentrations and allowing the animal to soak for 15 minutes daily."
Let us know which you decide and how the wee dood gets on. As I said, maybe someone with 1st hand experience of such a problem would be able to give you better advice on it all than I. xxxxxxxxxxxxxxx