Question: How can you adjust the bone roll value without twisting and deforming the mesh? If it does twist and deform can you reset the mesh to adjust to the new roll value of the bone?

For example I adjusted a finger bones roll to 250 so that the bone will go only follow the natural motion of a finger when extending in and out.

However after I did this the mesh around the bone its self was twisted. 
I tried deleting the vertex group and resetting it to the bone but after i made the new group and assigned it to the bone the mesh was still twisted. I tried resetting the bone roll with control-n to no avail. 

[![](https://blend-exchange.giantcowfilms.com/embedImage.png?bid=2197)](https://blend-exchange.giantcowfilms.com/b/2197/)

[![enter image description here](https://i.stack.imgur.com/9a9l6.png)](https://i.stack.imgur.com/9a9l6.png)

[![enter image description here](https://i.stack.imgur.com/1q1uP.png)](https://i.stack.imgur.com/1q1uP.png)

Answer: 
The only thing that ended up working for me is

1. Have no bone constraints on bones you want to recalculate roll(clear them - redo after), also clear all transforms (your active pose (Pose Position) should match your rest pose) on all bones in pose mode, save all poses in pose library
2. Clear roll values (`Alt` +  `R`) on selected bones
3. Change roll values to desired ones (or recalculate with `⇧ Shift` +  `N` or from the armature panel (global Z+ works the best)
4. Your mesh is now deformed in Pose Position, looks good in Rest Position, usually twisted odd ways around
5. You go to pose mode, select all bones and hit *Apply Pose as Rest Pose* (`Ctrl` +  `A` or select from pose panel)
6. Your mesh should now look good and all poses from pose library should be usable.

I do not have that version of Blender any more so I was not able to do much with the blend file.

Tested on Blender 2.93.5
You can unparent the mesh, roll the bone (in edit mode) then reparent the mesh, and it should work.