I used to chew on things when I was little. I would suck on my hair, chew on necklaces, I can't even remember all the things now. Since I've been on this board, I realized that I had lots of things that would have been diagnosed as 2e/SPD, but they didn't have all of that back then.

I'd say if there are treatments that seem reasonable and work for you, go for it, otherwise she will probably grow out of it. At least, I did.