Thank you for your question and pictures posted. I suggest you return to your doctor who has been treating you as he would probably know your history and evolution of this rash best as he has been following up on your condition.
This is because simple, uncomplicated tinea corporis is usually treated with topical anti-fungal therapy with good response in 2-3 weeks, provided you also control the risks factors that contributed to its development (e.g. washing clothing/bedding/towels in hot water). If topical medication does not work, a short course (up to 2 weeks) of oral antifungal therapy should work.
However, if both topical and oral medication does not clear your rash, it may be important to consider whether this could instead be another condition apart from tinea corporis. Your doctor should be able to advise you more if there is a suspicion of this from your history and by doing a physical examination.
