Thanks for the query.
You might be suffering from a mixed fungal and bacterial infection.
It is called as intertrigo
It is very common in folds of skin.
You need treatment with both anti fungal powders as well as anti bacterial creams.
Please meet a dermatologist
and discuss regarding this.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.