You have either probably picked up a fungal infection or have developed contact dermatitis. You can try applying an antifungal ointment known as Lotrimin, available without prescription. You need to also apply a steroid like 1% hydrocortisone, also available without presription at least twice daily - this should help the rash to go away.
Please avoid the pool for at least 1 month to help the rash clear up.
Before you go to the pool, please apply a layer of vaseline over the rash to prevent excessive contact of water with the rash
I hope this helps.
Let me know if you need more input. If not, please click on the green"Accept" button on this page. A positive rating and adding a bonus will be warmly appreciated.