Someone posted not too long ago about their daughter licking things and putting her hands in her mouth (IIRC). I can't remember who, and I cannot find the post!

Anyway, I was looking for it because DS2 (3 years old) has lately been chewing on his the point where he has scratches and teeth marks on his hand. He doesn't necessarily do it when he's angry...more often than not, it's when he's watching tv intently or falling asleep. Sometimes it can be his index and middle finger, sometimes his thumb, sometimes his entire fist. Yesterday, he fell asleep at naptime with it in his mouth and I had to pry it out. He recently has been having behavioral issues, too (his babysitter refuses to watch him b/c she's going through some personal issues herself, and she said that it's too stressful for her to watch him), so I'm wondering if somehow the two are tied together?

Anyone have any experience with this?

Btw, he's been sick twice in the past couple of months, and I'm sure that has something to do with it, too, since he's surely transferring germs into his mouth.