My 27 Month Old Is Biting Herself When She's Angry, How Should I Handle It?

My grandson would hit himself when angry or frustrated at around that age. My take was that he was not allowed to hit or hurt other people, and he was the least powerful person in any exchange, so when he felt a strong urge to strike out, he was his own target. This was most likely to happen when he was being reprimanded or corrected, which seemed to increase his sense that he should be punished.

We showed him how to express anger physically on an inanimate object, like pounding on a pillow. We gave him words to use, "I feel mad (or sad)." We gave him very clear permission to express himself in those ways. And then we pretty much ignored the times he hit himself. Within a couple of weeks, he was no longer doing that.

Developmentally and neurologically healthy children most commonly bite themselves out of frustration because of their inability to express emotions through other means. Thankfully, they usually won't purposefully inflict pain or do damage to themselves. Work with her and teach her how to use her words to express her anger, and behavioral ways of expressing her emotions like Peg suggested by pounding on a pillow or running outside until tired.

Also, do take her in to see her pediatrician. In some cases severe emotional stress or an uncommon neurological condition can be the cause and you want to rule that out early on.

If she's not breaking the skin, I wouldn't make that big a deal out of it. It's probably more of a sensory thing than an anger thing. Just keep telling her we don't hurt ourselves and try to let it go. If you keep harping on it, it becomes more of a thing to do because momma says not to than if you just let it go.

If she is breaking the skin, I would clean it with alcohol (slight burn to clean might have a tendency to deter) and apply neosporin.

good luck!

It's not hard to leave bite marks on tender little skin. She's obviously quitting before she bites hard enough to do actual damage.
I would try ignoring it. She will soon see that biting herself serves no purpose and hurts no one but her.
She might not even be biting herself that hard and just applying continued pressure which is leaving the marks.

Best wishes.