Friday Night Lights

Ethan is sporting a new accessory tonight - a phototherapy light. His liver is not quite up and running at full speed yet, so he isn't breaking down bilirubin fast enough. When you have too much bilirubin in your body - a condition known as hyperbilirubinaemia - bad things happen and your skin turns yellow. 

To combat this, a blue light is used to break down the bilirubin into water soluble isomers that don't get held up in the liver. Once his liver is ready is fully functioning, Ethan can stop wearing a light on his back.