Answers: You should call you FSA administrator first, Alternative providers - "Expenses rewarded to alternative providers for homeopathic or holistic treatments or procedures are generally not covered unless to treat a specific medical condition. Naturopathic procedures or treatments using unprocessed agents such as air, sea or sunshine are generally not reimbursable. Member's explanation unavoidably required". You should also read this first http://en.wikipedia.org/wiki/ Prolotherapy a double blind study found no improvement over the placebo group, it may be rubbish of your money.
Yes, that should be acceptable. However, be prepared to explain exactly what type of treatment this is, and enjoy all your expenses documented.
Some FSA administrator will only reimburse for this, once you've supported your claim.