Thank you for your query.
It is very difficult to say whether the rash
is due to chlorine allergy
without having a look at the rash. It is always better to make your daughter wear swimming goggles while swimming. It shall give her some comfort.
You can apply a hydrating lotion or oil like coconut oil, etc. over the rash to soothe it. While applying lightly she should keep her eyes closed so that that the eyes are not affected.
I hope I have answered your query to your satisfaction.
Wishing your daughter an early recovery.
Rajiv K Khandelwal