Hi and thanks for the query,
it would be appropriate for you to get a proper physical examination done by your physician. Your suggestions are all reasonable possibilities.However, knowing the exact causative agent and extent of the disease could be more informative in prescribing a more appropriate drug for a given duration of time adequate enough to lead to complete healing. Remember that certain skin conditions might warrant additional examinations which would not be gotten without a prior medical examination. Consulting your dermatologist
or family physician is my advice.
thanks and best regards,