Hi, yes, Salisilic acid can protect plants from fungi attack via direct toxicity to the fungi cells and via induction of plant self-defense mechanisms.
Since the fungus is on the top layer of your skin, it can be exfoliated off. Use either a salicylic acid or urea cream to speed up your skin's cell turnover. Ultimately, you want to get rid of the top layer of skin. Adding one of these exfoliants to your anti-fungal treatment will speed up that process.