From history it seems that you might be having fungal infection
in the groin.
Due to itching there might be having secondary bacterial infection.
Go for one antibiotic medicine course.
Apply antibiotic cream along with anti-fungal cream.
Afterwards go for oral anti-fungal tablet like Flucanozole course.
To control itching take Cetrizine
for few days.
Keep local hygiene clean, dry and airy.
Ok and take care.