Hello, Welcome to HCM. Your rash is a kind of ring worm caused by a fungi (known as dermatophytes). You need to apply anti-fungal cream on the affected area. Ketoconazole or clotrimazole ointment are good options to start with. Along with this, topical steroid cream like betamethasone or clobetasone should be used for short time to relieve itching. You can also take levocetrizine if itching is very much bothering. In certain cases where infection is extensive, oral anti-fungal medicines also need to be taken. In such case, you need to consult a dermatologist. You should also keep your diabetes under control and have a health weight. You should wear light cloths which prevent excessive sweating and rubbing on the affected areas. I hope this will be helpful. Take care.