My DD, who'll be 2 in November, has recently started to bite her own arm quite hard. Today she left three sets of bite marks on her wrist which were still there six hours later; she didn't make any noise about it at the time and I think she only stopped because I noticed her doing it and told her to stop.
She's a cheerful, playful, affectionate child and this behaviour seems very odd (and potentially dangerous?). I've found lots of advice on MN about children biting others, but haven't found anything about them biting themselves. Is there anyone else who's experienced this, or could shed some light on a possible reason for the biting?