If she's eating from plastic bowls, it may be worth swapping for ceramic or stainless steel. Plastic can sometimes be an irritant in itself, even if they are boiled clean every day plastic may still create problems for sensitive mouths. I think you did right getting her straight back on her normal food, it may have been something in the new stuff that didn't agree with her.
Not heard of the Eosino.. thingy
The little blue ceramic bowls are on offer at Zooplus at the moment, I got a couple with my last order and they're very nice.
Hope she continues to improve, Souffle.