Hello~
Her reaction could have been due to the peanuts, but it could also been caused by the extremely dry air in the cabin, lots of folks get dry eyes when flying due to lack of moisture in the air; it is really hard to say to be honest.
If it had been due to the peanuts, I doubt if the conditions would have gotten worse, usually they present themselves about as heavy as they are going to get, but then again, with peanuts, it is difficult to ascertain.
Does she have an epi-pen? If so, make sure it is carried if you fly again, better to be safe than sorry.