Hi, I did review your concern. Verruca on feet need to be examined before being treated. A biopsy may be warranted if needed. You are doing right thing by going to see a dermatologist. Verruca is generally due to Human papilloma virus and antibiotics dont work with them. they are generally treated by surgical removal, salicylic acid(Over the counter), Imiquimod and few other options. however first a confirmation by dermatologist is necessary as there are few other lesions that look like verruca but are actually not verruca pathologically and need a different treatment. I hope this helps. Wish you a healthy life ahead.