When I had warts as a kid I was told that you have one main wart which feeds the rest, so if your daughter has one wart larger than the others, this is probably the feeder. Treat this one with Compound W from the chemist's and file it down with a nail file every night - but not so you make it sore. I hope this helps.
I had lots of tiny warts on my hands as a child. A doctor, who was a close friend of my parents, rubbed a half crown on them and buried it in a secret place in the garden. Within weeks the warts had vanished - and the obvious explanation is that because he was a doctor, I was young, and I genuinely believed it would work - it did! He told me years later he had kept the half crown, too.
Compound W is the way to go, but don't file it is not necessary just reapply but only on the area affected. I just the wooden end of a match stick to apply to the area. It just crumbles away and with no pain. It may leave a little red patch but this fades but apply it until the skin area is flush with the rest of the skin. When removed but still red she could use a little cosmetic colour to hide the reddness. You are not supposed to use it on birth marks or brown moles ask your doctor if this is the case. Good Luck