In the UV editor, hold shift and hover your mouse over the arm, press L. Enter face select it will automatically switch to face select in the 3D window. In the UV editor, enable keep UV and edit mode mesh selection in sync.
I didn't see any problems with anything else other than the polycount and some topology issues around the neck and the side seams.Įdit: Nope. Either way, you'll end up with a bone_bone_shape and possibly another rig - actually, you have a bone_bone_shape in your scene right now so you'll end up with two. Or, delete the rig and all of its contents, save your file and close Blender then open your reference mesh, delete the reference mesh so that only the rig is left, then append your mesh. You can fix this two ways: you can either delete the rig and all of its contents then append the rig from your reference mesh be sure to select all of the body parts listed, as well. If you unfold it in the outliner you'll see what I mean.
Well, your rig doesn't have any body parts in it.