Knowing your daughter's age would help the solution. Let's assume she is pre- kindergarten. I would form a team with the daycare people to assess the behavior. Is there something going on at school to develop this habit? or is this self stimulating behavior. Talk to her and tell her when doing it to divert the behavior. If she feels the need to pinch, tell her to put her hand on her knee and press (alternative behavior) often stops the original problem.
Wayne Yankus, MD, FAAP
expert panelist: pediatrics
Pinching could be a behavior that your daughter learned to to get attention. Sounds that she is doing that at daycare and now at home. Ignore these behaviors or distract her from them and hopefully after a short while she will stop to hurt herself! However, if she continues on, pinching becomes more intense and frequent, your daughter harms herself, or becomes mean to other children and/or animals, talk with her health care provider.