Would the teacher be mad at me?

Okay, I am a TA's aid. And (I'm a student) I have her as my teacher too. Well today we were passing out this graded test. And I graded that paper. But people were complaining that their test grade was wrong. Well the day I was grading them, another TA came in (she is a TA for a different teacher.) and helped me grade some. I think the mistake ones were from her; but my teacher doesn't know and I'm not going to blame her. But do you think the teacher is mad at me because of the wrong grading?

i think you need to come clean with your teacher and apologise for what has happened + you will personally re-grade all the tests ... it is always best to be honest and to have things out in the open

In my opinion your teacher should not have a student TA grade papers, and especially not if the student TA is in the class! Hopefully the tests were somehow anonymous so you didn't know who was getting which grade. I don't know if the teacher is mad at you about the grading, but you shouldn't worry about that. The teacher should take this as a lesson that she needs to grade her own tests. That is not something a TA should be doing.

Are there marks on the paper that can distinguish one grader from the other? In other words, different handwriting or pen color or anything? I am not sure that I would take the blame for this one if I were you. I know it feels cheesy and as if you are ratting someone out, but, honestly, you have to figure out whether taking the fall is going to hurt your reputation more than being thought of as incompetent. This experience may end up providing you with references for the future, etc. Stand up for yourself. Say, "You may not be aware of this, but I was not the sole grader on this test. I am not sure that the mistakes are mine." (Something like that.) There are times when it doesn't matter if you are "big" and take the blame and there are times when it does matter and you need to protect your image. This is one of the latter times, I think.