I was looking through my daily Esty newsletter e-mail and in it I saw the perfect to add to a Goa'uld ribbon device, it's an LED light kit that fits in the palm of your hand. There is a cable that runs from the LED to a wristband where you put the battery but I figure that a lot of that could be hidden inside the ribbon device itself or the sleeves of your costume if necessary.
Check it out: https://www.etsy.com/listing/214207110/hand-energy-blast-mini-led-light-kit