This is an illuminated ring mixed from the clever skull designed by MacGyver.
If you are thinking of a talking skull for Halloween, go back to his files--the upper jaw and lower jaw can be separated.

Print at low resolution with supports. Clean out the supports. Tape a LED to a 2032 battery and insert the battery in the ring.
If the ring size is wrong, then life gets more complicated. Go to Tinkercad.com and load the "skull without ring" at 100% size. Load the "ring for skull" at > or < 100% (depending on whether you need it larger or smaller. Combine the two in TinkerCad, group them, then export as a printable (.stl) file.