Dear Parent, based on your history it looks like your daughter may be suffering from a viral exanthematous reaction. This could be confirmed by some blood tests.
If this is the cause, your daughter will require conservative management till symptoms subside and she feels better. This may take 5 to 7 days depending on your daughters immunity to cope the condition.
Conservative management means:
1) You'll need to take care of her hydration (minimum 2 liters or 6 to 8 glasses of water per day).
2) See that she eats well. As she has
fever she might not taste the food well, so give her some bland food like cornflakes, etc.
3) Manage symptomatic treatment, eg.
antipyretic tablet for fever, antihistaminic for
rash, etc.
I hope could answer your question. Wishing you and your family good health.