Before you just use crazy glue, consider that it is hard to remove, and is stronger than the skin – so you may pull off some skin if you just tear the jewel off your face. (Crazy glue is removed with).
Here is a “Straight Dope” discussion:
From Yahoo answers:(My take-a-way: you can buy rhinestones that are adhesive backed)
Sourced from Amazon (for convenience and reference):
Please be careful, and Have a sparkling good time!