You need to see another doctor. Green discharge in ANY female of ANY age is an indicator of infection. Yeast infections (also called thrush) often produce a white, chunky (yuck, but think cottage cheese)discharge that smells slightly odd. Not fishy, just not normal. I know this will sound harsh, but did they at least open her labia up and look at the vaginal opening? Toddlers will sometimes insert things into orifices (vagina included) and if she has something in her vagina, it NEEDS to be removed. Especially if she is having signs of infection, ie. greenish colored discharge. I would definitely seek a second (or third or fourth) opinion or take her to the ER.