My son had pica too. It all runs its course then subsides. I would give my son a seperate shirt to chew on...like a wooby shirt. Also tried chew tube. The good side is that if there is communication issues its good that the mouth and tongue are always in motion. My son has severe apraxia and if school had worked with that appropriately, things would be different today. I would work more on shifting the chew then trying to remove it...that will increase anxiety. This too shall pass:)

We have same issue. We use chewies a lot, but he still likes his shirts. We have found that the actual material and cut helps. For example - all his cotton tees have holes in them. But the cotton v-neck tee and sleeveless and the "active wear" material (the kind of shiny) he doesn't like to chew on. He doesn't like anything up around his neck too high, so I think that may be part of it....at least for our kid.

We use a chew tube as well. Also grandma took out her sewing kit and transformed long sleeves into 3/4 and that helped a lot too. Our OT is introducing gum to her in sessions with the idea this someday could be a more socially acceptable way to deal with this.

Our son used to chew up soda cans, pens, pencils, his own flesh. It was extremely difficult to get him to stop. There are many different chew type toys/jewelry/necklaces available if you search online. There are companies that have specialty products/lines that they make just for this. We had to do a lot of experimenting with different types of chew toys/items before we finally found one that kind of worked. It did not 100% solve the problem, he eventually grew out of the main chewing phase as he got older (thank goodness).

We used homemade cloth neckless first, then slowly introduced chew necklaces.