I would have to disagree with the person who recommended against Sativas. High quality sativa dominant strains are better for migraines in my opinion than indicas, because you can get burnt out a few hours after consuming indica bud, especially if it's been smoked more than once in a day.

Also, with indicas its been my experience with migraine sufferers that they can smoke indica to relieve a headache, but then a few hours later during the burn-out phase the headache returns, accompanied by exhaustion.

I would recommend sativas specifically because in general sativas leave the user mentally nimble and clear-headed. Sativas are generally used by people in the morning, before they go to work or when they have responsiblities to attend to. They leave you energized as opposed to the Indicas which have more tendency to leave a person lethargic, drowsy or foggy-brained.

For nausea, both indica and sativa should work very well.

If you'd like to try something in between, a great strain for a child would be blueberry. It's got a great taste and odor which is more pleasant no matter how it's consumed, it's got anti-nausea properties, and it's a hybrid so it's got both indica and sativa properties. It will leave her more clear-headed than most indicas and may provide stronger pain relief for severe pain than most sativas. It will allow her to retain enough energy to function. Even its name is kid-friendly.

So if you start with Blueberry, you can take note of how she's reacting to it and go from there. If she needs more pain relief and isn't having trouble focusing you could drift more to the indicas, if her thinking is too cloudy or she's having trouble staying awake but shes not in severe pain you might prefer a sativa next time.

I would say that Indicas are useful for immediate use in the case of acute and extremely painful migraines, and Sativas are for long-term use of day to day headache prevention and relief from less extremely painful episodes.

I wish you the best of luck in finding the right medicine for your daughter. If you have any further questions, feel free to contact me.