I agree with the other doc. We would not necessarily need to see a child with simple, uncomplicated chickenpox.
Many parents, on the other hand, will confuse any rash illness with chickenpox. You should be able do make the diagnosis if you look at new, fresh unbroken lesions very carefully. Chickenpox first form as a tiny, fluid filled vesicle or bubble, with a tiny red ring around the base. They used to call it 'a dew drop on a rose petal.'. The little bubble ruptured fairly quickly and then turns into a crusted or scabbed over sore. More common these days are a multitude of minor rash illnesses that typically consist of tiny red bumps. These do not have vesicles.
We tell parents to come in if any of the red bases enlarges to a nickel size or larger, or if the child starts to act really ill. The feared complication is a strep secondary infection of the open sores.
Taking a photo is a very good idea. The child will need to be immunized to attend school (and day care in many areas). If she has really had chickenpox she will not need the vaccine. Without evidence, you may be requested to get a blood test later on (IgG varicella) to prove her immunity.
One last thing. Keep her cool, not overdressed, andcshe will get a milder case with less pox.
Hope that helps.