I started weight painting a little bit, then I realized I shoulda had an extra bone. So I added it, but at this point, I believe *parent to armature with automatic weights* would destroy the previous weight painting.
If you're adding a new bone to an already-parented armature, you simply need to add a new vertex group and copy the name of the new bone to that vertex group. That will maintain all other weights and allow for painting weight for the new bone.
