Picking the skin off your foot can be considered a form of self-harm, especially if it is done repeatedly and stems from a desire to cope with emotional distress, anxiety, or other underlying issues. Self-harm often involves intentionally causing pain or injury to oneself as a way to manage difficult emotions or situations.
If you find that this behavior is persistent and causing you distress or harm, it might be helpful to talk to a mental health professional. They can provide support and strategies to address the underlying issues and help you find healthier coping mechanisms.