How Can Vaginal Area And Thigh Patches Be Treated?

Hello doctor, my 6 months old baby was suffering from cough since 2 weeks, we put her on antibiotic for a week and now she is fine, but suddenly we noticed red patches like pimples all over her vaginal area. Also its spereading on thighs also. we are applying coconut oil, sebamed diaper rash creams and hot cotton dipped in coconut oil. But no improvement. Please guide me something what can we do. Best Regards Kapil Mehta