From Second Life Wiki
This practice is supposed to give the avatar a nicer look. However, some Residents became annoyed by the use of facelights, since they may also influence the lighting of their surrounding, or make avatars look bleached out, depending on your Environment Settings and graphics settings.
How to create your own facelight
- Go to a region where building is allowed
- Click the Build button in your task bar
- Your mouse arrow is now shown as a wand
- Click on the ground in order to create a prim
- Click the Texture tab in your build menu
- Click the Texture window and search for *Default Transparent Texture
- This is a texture located in your library. Just type the name in the search bar.
- Highlight the texture and click Select
- Go to the Feature tab and check the Light checkbox
- Adjust Intensity, 'Radius and Falloff' as needed
- Pick the prim up and attach it to a free spot on your head (preferably Nose, Mouth or Chin)
- Highlight transparent items (View > Highlight Transparent or - - )
- Adjust spot and size of your facelight by editing it
You can also have a look at this video tutorial at 2:37.
How to turn off attached light sources