I would probably rather see a crayon eaten than a piece stuck up his nose. (I had THAT dr. visit with a bead - WHY do kids do things like that???) If part was bit off and it is in his teeth, there's a chance he chewed up most of it. Just keep brushing well and eventually it will come off. Also, call the dr. because drs and nurses deal with calls like this all the time. They may have better advise for getting it out of his teeth. Good luck.