Kindly share pictures of the affected area to help make a correct diagnoses. For the time being you can apply a simple antiseptic cream called fusidin cream over the affected area twice a day and adsorb powder over the affected area after a bath.
Next Steps
It is better to consult one on one with detailed history and pictures to help resolve the issue faster.
Please understand there are many conditions that can affect the groin area, I have only prescribed a temporary and general Solution.
Health Tips
If you are a diabetic, strongly advise you to get your levels tested and keep it in check
Keep the area as dry as possible and avoid wearing undergarments till the problem comes down