Found this cool little rechargeable led on aliexpress and super cheap. I modeled a base to house the light and be able to charge it while in the skull. I have attached a link below for the exact light i used

$3.20 | 3D Moon Lamp Accessories Rechargeable Light Board 16 Colors Led Lunar Light Data Cable Remote Controller for Kids Room
https://a.aliexpress.com/_mPSRoIi

really simple assembly. Place the light charging port into the base and secure with a little bit of glue. once dry. clip the base into the skull