Hi, Welcome to HCM. Rashes at a particular anatomical site can be due to excessive sweating, some allergy, non-infectious seborrheic dermatitis or contact dermatitis, etc. You should apply 1% hydrocortizone cream for a week or 10 days or 1% clotrimazole cream if you suspect it to be fungal infection, anti-histamines like cetirizine and medicated lotions and moisturisers can be helpful. Non-infectious rash generally go away by themselves in 10 days. Take care of your hygiene, wear cotton clothes, avoid eating oily or spicy food. Keep yourself well hydrated. If rash still continues, see a dermatologist, get clinically examined, take care.