No one wants to see their child suffer any kind of pain, I understand that and can sympathize with you. I hate to see my children in distress. I'm going to address a few points, so bear with me, OK?
First, I'm glad you taking action with the school and they are being proactive in their approach. There really isn't one set answer for a 504 plan for students. Much of the answer depends on your daughter's Migraine triggers and, of course, her individual needs. You may want to have a conversation with both her high school counselor and her doctor on this topic. Her doctor should be able to help with helping you anticipate her needs, and the counselor will have experience with what's been done for other students We have a thread in our discussion forum called Chilrdren and Migraines that addresses these issues. Here is the link, please go over and take a look at it. Many parents have been where you are now; Children and Migraine.
She really can't continue to go on with this continued daily pain. Has the doctor offered anything to break the cycle? Unfortunately, there can be times when a Migraine just doesn't respond to the medications we have, and it goes on and on. Seeing as her regular medications haven't stopped this Migraine, it's time to talk to the doctor about breaking this cycle. Sometimes, a steroid taper such as a Medrol DosePack will break the Migraine. Sometimes, the best treatment for intractable Migraines that aren't responding to medications is IV infusion therapy to get the cycle broken. For more information, see IV Treatment of Refractory Migraine.
Which leads me into my next point. It may be a good idea to see a "true" Migraine specialist. I say that often here, but it really is the one thing that can make all the difference in the world. You see while neurologists may be fine doctors, they have a hard time being experts in one area. This is because they treat so many conditions like MS, epilepsy and stroke. A Migraine specialist is just that, an expert who treats one condition - your daughters - Migraines and headache disorders. When you get a chance, take a look at article Migraine and Headache Specialists - What's So Special? If you need help finding a Migraine specialist, check our listing of Patient Recommended Migraine and Headache Specialists.
I hope you find this information helpful, please let me know how you make out,