The lights each have their own batteries, they're all individual. You can get them in all different colors as well, heres the amazon link it you're interested.

SumDirect Pack of 12 LED Mini... https://www.amazon.com/dp/B00LZUX0E2?ref=ppx_pop_mob_ap_share

Light it up for the night! LED string lights or a single red one hidden inside the skull.. You could experiment with diffusers to make it a softer glow.

If you want lights in specific spots with specific colors, you might wire it up yourself with conductive thread and LEDs.. like LilyPad LEDs or Adafruit LED Sequins