Retraining your arm is the goal, not making pretty little circles and lines first time out. Now gently insert a pen, separating those fingertips it is unlikely this is your normal pen grip.
Let it do the work.
It makes writing painful and jerky. The abnormal postures and involuntary movements begin soon after you pick up a pen. Trigger finger can develop when the tendon is swollen or nodular and cannot move smoothly through the sheath that surrounds it.
This will demonstrate how really little muscular effort is required to move the pen. To get a feel for the proper muscles and start training them correctlyhold your arm out in front of you, elbow bent, and write in the air.
At the wrist, they pass through a fibrous sheath. In both, the remaining fingers are curled under the hand.