Aloha Hakim,
The sensation you feel in your hands as Qi fills them from the focus being brought there can and will be different over time as your perceptions being more sensitive.
Whether it is you opening to a physical sense of this, or whether it is a balancing of blockages in one or more of the channels running though the hand, is unimportant. Continuing your exercise and allowing it to balance.
You may experience a variety of sensations, images, and smells during your practices throughout your life. Chunyi would remind you to acknowledge them and bring your focus back to your exercise.
Much Love, Shawn