Question

what happens if you eat a small piece of glass

Answer 1

You don't need to worry. There is only slight chance of happening something bad. I have seen small kids swallowed about 5cm needles and pass those with stools after couple of days without any intestinal perforation. If you are not having severe abdominal pain, not passing blood with stools, not having abdominal distension basically you don't need to worry. Eat more bananas. It will ease passing these glass particles with stools.