[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/txaY0.png

I'm fairly new to using Blender and have been able to understand most issues on my own but I can't find an answer with this one. 

When I weight paint my mesh's [ body, mouth, teeth, etc. ] they weight paint just fine but when it comes to the tongue I can't seem to do anything with it. When I click the bone in pose mode and then the mesh and go to weight paint it just looks like how it's shown in the picture.

Please help.