No need to worry . They are not toxic . But is it a regular thing that she eats non edible stuff like mud , chalk etc . If so then it may herald some  deficiency . Give Calcium and Vit D . Check Haemoglobin . If low then iron supplements to be started

Crayons are usually non toxic. They are made up of wax and colouring agent so by enlarge a non toxic substances. However depends on the company. Immediate problems can be choking if the child has ate too big a piece. Usually they are mild laxative so can cause stomach ache and some loose motions and that is normal. To avoid such episodes, use art materials which are non toxic, food colouring agent and unscented. Mostly it is pica (behaviour of non nutritive substances). It can be out of curosity. Some times due to nutrient deficiency or development delay.

Hello , nothing make sure she won’t eat again.