Finger bitting

For a couple of days I noticed my 3 year old putting thier fingers bitting them. She sometimes pulls on her teeth too. Today it was just to much we were at the store and just kept putting her fingers in her mouth bitting or licking them. She even said yummy. What does it mean. I don't thing is her teeth we brush them everyday. Am worried if is anxiety cause am not sure were she couple have gotten it from. I ordered a chewing toy for anxiety it arrives tomorrow. I can't help but to feel nervous I don't want her to use bitting her fingers to help her regulate. And this is just happened out of nowhere.

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