8 year old has rash around private area.

As the title states my child has a rash. This morning I was called into work so her grandmother stepped into help. However, after taking a shower (used all the usual shampoo/conditioner--no soap on vaginal area) ... but when it was time to get dressed my daughter didnt put on her under wear (she always wear underwear lol but not today)She wears a school uniform (skirt with built in shorts) that has been washed in the same detergent as always.

Symptoms:

The rash is red and is on both sides of the inside of her thighs. Also the "labia majora" is also red however there was no evidence of discharge. It honestly reminded me of when she had a diaper rash as a baby. She complains of pain. No itching though.

She's 4'8" 65 pounds. I applied hydrocortisone cream to the outside but she says it didnt help. (Besides that no other medication) I also have a tube of Nystatin& clotrimazole cream that hasnt been used.