Problem with blender and csgo model

Hi, i have a problem when i try to add new bone into a model.
I’m trying to port a model to csgo but when I create the bone and the vertex group called “finger_middle_meta_L”, the bone dont turn up into a sphere

https://gyazo.com/f9441fc2118c4fb79921ce5c640283a4?token=07e60712b427ba5e0ca60d99b44c7c07

who is the problem?

Srry for my bad English :frowning: