He won't hurt himself, he's just playing & exploring his world, relax.

His teeth will come through in their own good time, but give him some crusts, crackers, rusks or similar to gnaw on this might help stimulate their arrival. If he still has no teeth next time someone in the family id going to a dentist ask them to ask about sean & how late you should leave it befoer having him x-rayed - which is the only real way they can see what is & is not happening re his teeth.

I work with infants and they do that all the time and all so they are growing very differently so don't worrie he'll get some teeth soon