Hi and thanks for the question,
I know how distressing this could be, having to take the same treatment many times for the same thing. However. i would love to know the longest duration of the treatments you have taken. Some chronic skin infections might require treatments going over months.
I would skin have skin biopsies, cultures and sensitivity tests done. This shall grow and identify the exact causal agent, and the specific drug required to eradicate the infection shall then be identified. Consulting a dermatologist
for a complete reevaluation is great idea.
Thanks and hope this helps,