Cocount Bear - I applaud you for all the support you are giving your daughter, in trying to find relief for her pain! Please don't stop, I wish my parents had taken me to doctors. Since I see how thorough you are, I just want to share my experience in case it helps you think of anything else to try.
I've had migraines for the past 18yrs, since puberty. I remember walking home from school, barely getting in the door and collapsing into bed for the rest of the evening/night. Back then all I knew to do was take aspirin and keep icing my head. I assumed my migraines were due to all the exhaust I inhaled while crossing Dixie Hwy on my walk home. (In retrospect, I sure wish it had been that simple!)
I have always needed zero light/sound/smells/movements, and my pain was always explosive or stabbing. I usually start out with sensitivity to light, or I start seeing some blotches, or I might even start talking a bit confused or slurring my speech, or I notice myself start rubbing my brow - that's my first clue. It starts in the brow, bridge of my nose, eye sockets... spreads it's way to my forehead and temples - usually one side, and it often switches sides throughout the attack. I usually feel nauseous but only vomit occasionally. And of course once it is over I am usually exhausted and excited all at once!... and hungry! LOL.
Once I was 18 I started getting MRI's done. They found a cyst near my pituitary gland and I was all excited (thinking they found the cause!) but they said "eh, it's not on the brain so it's not causing it" and that's the same thing they (several neurologists) have been saying ever since. Let me also say, that I have never had regular cycles since puberty, either (I doubt that has anything to do with your daughter since she started migraines much earlier than puberty, but just saying - hormones can be a delicate thing). My doctors always shoved me on birth control since I was 15 years old. I always got tired of it and stopped taking it, mostly bc I was afraid my body would "get used" to it and give me fertility issues. (Having 3-4 periods a year meant I already had fertility issues anyway LOL).
In my 20's I tried Imitrex (did nothing for me), MaxAlt (I liked it), and I tried Zomig just once (it didn't work, and I figured it might be potent so I didn't take anything else... I was afraid to "waste time" trying it ever again bc I was afraid it wouldn't be effectve - again). I also took Ketorolac which I think helped but can't recall. I also took leftover hydrocodone (leftover from when my wisdom teeth were cut out) because I remembered it helped knock me out and I just really hoped to sleep off the migraine. When I was 27 I saw a wonderful Reproductive Endocrinologist who finally told me why I had all kinds of cycle problems - I had PCOS - Polycystic Ovarian Syndrome. My testosterone was way high, and several other hormones were very out of whack. My body had no intentions of doing more cycles than 3 or 4 a year (each would be 3 weeks of horrendous hemmoraging, and I was anemic as a result, had to get daily injections of liquid iron in late teens, early 20's). I fear I would've gone into early menopause! Anyway this doctor showed me how my ovaries were full of cysts (from eggs that didn't quite release and would build up on the ovaries - hence no periods for quite a while). He convinced me to do birth control for 2-3 months just one more time, to force cycles and clear out those ovaries as much as possible. I also was prescribed Metformin (interesting since that is mainly a diabetic drug, because both side of my family have history of diabetes). Then he did Ovarian Drilling - lasered several holes into each ovary. The ovaries had each been as big as my uterus, so this introduced them to a state of trauma which made them heal into a normal state. Then I got pregant 6 months later :) Anyway, my hormone levels were much better after the surgery, so I was hoping as a bonus that this would have a positive effect on my migraine frequency. Nope So that's why I'm throwing that story out there, just in case your daughter has any similar girly issues. Sometimes doctors would tell me my migraines were all in my head (ha!) and that they were probably just aligned with my cycles - I'd get so angry and inform them that I only had 3-4 cycles per year, and sure wish the migraines only came 3-4 times a year!
For about a year prior to pregnancy I had been taking Fioricet (generic is Butal) for my migraines. It is a acetaminophen/caffeine/butal mix. Acetaminophen does nothing for me but something about the caffeine/butal seems to help. (I recently found out about Fiorinal which has aspirin instead of acetaminophen - sure wish I had known that before, I would've taken it prior to pregnancy). I was allowed to keep taking Fioricet during pregnancy and nursing. I gave birth and then nursed for 11 months and got pregnant again. I sure do miss the option of aspirin (Excedrin Migraine used to be my best friend, and will be again one day). I've been to the hospital 3 times. All they do is give me Tylenol and an IV drip. I DO think the IV drip helps, probably for hydration, but I'm shocked that's all that they can do. The last time, during the nursing months, they offered a compazine injection. I had read some people say it helped them but some complained that it made them feel crazy. I asked the staff if it would make me feel crazy, and they replied "probably" so I turned down the offer. Also during nursing, a Neurologist prescribed a daily maintenance Nortriptyline. I picked it up, but after reading the pharmacy pamphlet I opted not to take any of it. More people reviewed on it about how they feel crazy if they don't take it (apparently it needs weaned off of, cannot stop it cold turkey).
My Neurologist told me I am a candidate for Botox, which the FDA approved a couple years ago for purpose of migraines (so, insurance covers it). I have to wait till I'm done nursing after this pregnancy, so I still have another 1.5yrs. But I look forward to trying it, as it gives 3-4 months of relief. I'd still like to know the underlying cause though. I asked a different Neurologist about PFO - a hole in the heart, which I read allows blood clots to slip through and causes migraines. After reading about PFO I was sooo convinced that I had it! He thought it was all a bunch of hooplah that hadn't been throughly verfied yet. Ugh! Sometimes I feel like they don't even try to look and see if you have the very thing you are asking about. I'd also like them to remove that cyst near my pituitary gland, as it'd just be nice for them to rule it out completely. It doesn't need to be there anyway, it potentially could've caused my hormone issues. Afterall, they did prescribe me Bromocryptine at one point, to shrink the cyst. I've also read about some doctors claiming that some people's nasal/sinus structure can cause migraines, and that slight adjustment of the structure can greatly reduce migraines as a result. I might look into that, just to rule it out, too. People with migraines know, that we will do just about anything to rule out a possible cause, or that might provide any kind of relief!
I know this was a long post - sorry, but I just wanted to spill out my whole story to you, just in case your daughter has any similar issues. I wish you all the best. It's no fun... especially when you are taking meds at least 3 times a week because of them, and then having phases where you get them daily sometimes for 2 days at a time! (I was soooo scared that I would get one on my wedding day... as it turns out, it came the day after - in full force, vomitting and all. It was incredible pain. I am SO thankful that it didn't happen one day sooner, as I would've eeked out my vows and then crawled into the hotel bed while the guests enjoyed the reception. Whew that was a close call!).