Weight Painting stretching out my vertices?

Hello! I’m trying to create a wrist and ankle controller for this rig that I downloaded. I’m trying to assign weights for the left wrist, but when I try to paint on it, it seems to somewhat inflate my vertices or geometry. I tried painting over the other limbs and I can do so perfectly fine. I’ve tried looking up as many videos as I could to resolve this problem but I’ve had no luck. Thank you very much!

https://gyazo.com/7f4083de8ece90bcb75830938f29942d

https://gyazo.com/383804c5c8264317385e8a73010059b3