I know I asked a similar question like this before, but I didn't get much of a proper answer. How do I make the knuckle joints of my character's hand "fatter" as they bend downward and if possible make the top part more "pointed" all without using Drivers? Also my character's using subdivision modifier right now.
This is an interesting technique, where the Mid bone is duplicated in edit mode. Switch the direction of the newly created corrective bone, make it child of the Mid, assign a rot constraint targeting the same Mid bone, with inverted XYZ, and assign some weight on the knuckles vertices.
The influence slider lets you control the amount of the effect.