May have swallowed a very small thin piece of my permanent retainer about this size (-------) should i be worried

Concerned: This is cause for concern, as it may scratch or tear the lining of your digestive tract. Eat and drink normally and be aware of any rectal bleeding or abdominal cramping over the next 2-3 days. Typically this will become encased in a covering and not be so sharp and pass through without incident. If any changes occur, get to the ER right away. Good Luck.

Wait and watch it to: You need to wait for a couple of days that it takes to go down the intestines and out through the stool. Unless you experience some pain in your belly, you can relax and not worry about it. I do not expect any serious problems. Good luck.