is it normal to get a rash between?

Hi,
Welcome to ehealthforum,
It is difficult to comment on diagnosis without examining you. If your own self treatment is not helping you, then it is time that you should consider getting an examination done by your doctor/gynecologist. It will help in identifying the cause. You might need to have a skin scraping test done form the affected area. Drink plenty of water. Avoid use of harsh sap, perfumes etc., in the area. Use loose cotton undergarments. If infection is detected, get your partner also treated simultaneously to prevent re-infection. Avoid intercourse while being on treatment course.
Take care.