Temporary paralysis of lower legs

[Dumb93]

My daughter called me to her room two weeks ago and couldn't move.  When she was trying to talk to me her lips were not moving.  About fifteen min later the paralysis receded to her lower legs below the knee on both legs.  I carried her to the car and took her to ER.  The doctor did tests including CT, Xray and tried to get spinal fluid from a Lumbar Puncture but failed to get fluid.  He (at the time) thought it was Guillain-Barre syndrome.  They admitted her to the hospital for observation and more tests.  They got fluid off of the spine the following day but all test came back normal.  On the third day in the hospital the numbness receded to just tingling in the feet with numbness in the toes.  She ended up spending 7 days in the hospital while getting 3 MRI's, a CT, a Lumbar Puncture (which she had to go through 3 times) and a pile of blood work.  She saw 3 Internal Med Drs and a Neurologist and the verdict was there was nothing wrong with her and sent her home with no answers.  Its been a week now and her feet still hurt and tingle all the time.  She is back in school (she is 15) and walks fine, just with pain.  Any suggestions or clues to what happened?