Seems like you have developed a fungal infection
ie Tinea infection...Such infections usually occur in summers due to increased sweating and improper hygiene....Firstly avoid using any kind of oils or moisturising creams over the affected region....wear cotton clothes and undergarments...take bath daily ..You might need to apply a topical antifungal
cream (something like clotrimazole
gel) over the region for atleast 2 weeks.....And yes, weight loss
will definitely help in preventing the recurrence of such lesions..
Hope it helps
Dr Geetika Paul