I feel guilty for something I didn't do?

Today in school, we got a project back. A boy was going to take the project to break it and everybody didn't actually care. Then at the end of the class, he said for everybody in the group to break it. All I did was push down on it and cut my wrist accidentally on a sharp part of the project. I didn't break it because it didn't move at all, and then the boy broke the project in half. The teacher came up to our group and asked who did it, and everybody said "not me". I didn't say anything because I know that I wanted to try but I didn't. Then I told the teacher that they did a draw because they were just going to take it home to break it. The teacher asked the people who were in the draw if it was true, my friend said it wasn't, even though it was. Everybody blamed everything on me and said that I cracked it in half and ripped it apart. The teacher said " How sad, this was a group effort and you all destroyed it. How sad" and I feel really bad because tomorrow is the last day of school and I feel like the teacher is disappointed in me. I really want to tell the teacher it wasn't me but I can't find the courage to say it. Now I feel guilt because everybody is saying that I did it, and I don't want to end the school year with a bunch of guilt bundled up. Most of the people in the group ruined it, but the boy did lots of the damage. I also got a cut on my wrist because I got cut on a sharp part and it looks like I actually did everything, I feel like I'm some kind of criminal. :/