What Causes My Daughter S Recurring Vaginal Swelling And Pain?

Hi,my 7 yr old daughter woke lastnight complaining of being sore down below.The area she says is hurting is her clitorious.It did look a little raised but not red. This has happened on the odd occassion before,always in the night & I cant think of a cause.The pain is obviously intense because she screams & begs for me to do something until she is exhausted & falls asleep,usually after an hour or two.By morning she is always completely better. We have tried having a cold flannel against her,showerin,sudocrem but nothing gives her any relief at the time.Is there anything you can suggest for if it happens again?