Hello, Welcome to HCM forum. Fungal infections are generally slow to begin and progress . They usually occur in moist covered areas or creases and in immunocompromised people . However many healthy people too can catch it. The best way to treat it earliest is to take oral and local antifungal medicines like fluconazole , ketoconazole or terbinafine which I assume your doctor has already started . It will take about 4-6 weeks for complete resolution . If still there is spreading do get reevaluated by your dermatologist for alternative stronger antifunfals . Try to keep the skin dry and open , you can use candid dusting powder for the same . In future adequate hygiene , avoidance of excessive moisture / sweating etc and a healthy diet and lifestyle can help prevent it.Get your blood sugar levels checked regularly as diabetics are prone to recurrent infections . Wishing you good health. Regards