Ester used to pick at mosquito bites when she was younger an…

Ester used tо pick аt mоsquitо bites when she wаs younger аnd found that it made her feel better. When her parents divorced, she began picking at her arm, causing it to break open and bleed. She would then pick at the scabs, preventing them from healing properly. Now she finds that she engages in this behavior automatically when she is nervous about something. What would be her likely diagnosis?