It seems like you are having Intertrigo
( inflammation of the skin in between the body folds due to friction ), once there is a break in the superficial layer of the skin then the Yeast which is the normal resident in the area due to moisture and heat favourable for them causes fungal infection
So I would suggest to apply Lamisil
cream two times a day for 14 days.
2:Zeasorb Af Powder sprinkled in the groins to reduce further friction while having a walk for te same duration.
I hope with above medications you ll feel much better.
Thanks a lot and all the best.