Does the calligrapher have a cocoon in his right middle finger? Is it because the pen is held in the wrong way?

Cocoons will rise, but not at the joints, but at the heel of the middle finger nail (pen). The primary school teacher is not responsible for the incorrect writing posture! Parents are dereliction of duty! The middle finger plays the role of support and balance, not the load, plus the gravity of the thumb, then it will be miserable! I suggest you correct it as soon as possible.