I'll echo everything said by the others here.

Does she have a good Pain Mgt. Dr. and a really good physical therapist?
There's no "magic bullet" or cure IF she has CRPS/RSD. It's a really tough balancing act. It is POSSIBLE to get the pain at manageble levels especially if PROPERLY treated as early as possible.
P.M. Dr.'s have a variety of treatment options to explore. I would recommend doing your homework on any really invasive ones.
In the short term, this will be time consuming & won't help in getting her caught up in school right now. But concentration is difficult anyway with that much pain.
For inspiration: My P.M. Dr. has 1st hand experience with this. She had it BAD when she was a teen & was wheelchair bound for some time. They finally got her into remission & of course she walks now. All I know is they finally got her inpatient treatment with drastic drugs.
I'm not in remission but very often my pain is at manageable levels, thanks to her.