Carmex! It heals them like magic :)

Oral pain reliever.

I would try a lot of vaseline or chapstick hoping that he wouldn't be able to get a good grip.

i used to pick my lips but I found little bit of water drank every so often helped chapped lips. Dont know whether will help but water every few minutes until lips feel better and you feel hydrated

Does he take a medicine? It was listed as a possible side effect for my son's medicine. It could be out of boredom or anxiety. My son has been chewing on things lately.