Ouch I'm sorry glass in food is dangerous.
You have to go to the manager immediately. The problem is if you didn't you really can't do anything about it now, well you could, but the chances of them being sympathetic or doing anything about it is slim because the more time you waited to say something after the meal the less credible you look.
I've worked in the food service industry before and there are a lot of people who pull stunts just to get a free meal. here are some tips to follow.
1. If there is something wrong with your food, bring it or send it back,immediately. Don't eat more than half of it and then ask to get another plate for free.
2. Don't embelish. Saying something like. "I come here all the time and the bacon is always better than this" is not a good thing to say if you really don't come there all the time. The workers will catch your bluff.
3. Don't ask for anything free. You are more likely to get comped meals if you are nice and polite and just let them know. Sometimes the less you ask the more they will take off your bill.
This seems like common sense but you'd be surprised how many people don't follow these simple rules.
My concern though is that if you didn't say anything they make have when opening a glass bottle had it break a little bit and some pieces of glass got in a pot of food. So it could be more than just you getting the glass. If you feel the need to say something you can call them up and let them know just in case they had a glass break in the kitchen. That way they can isolate the problem.

