It's a mental disorder.

Hello Try the following Do keep your hands busy – try squeezing a soft ball or putting on gloves identify when and where you most commonly pick your skin and try to avoid these triggers try to resist for longer and longer each time you feel the urge to pick care for your skin when you get the urge to pick it – for example, by applying moisturiser tell other people – they can help you recognise when you're picking keep your skin clean to avoid infection