Will the school find out who hacked into my account on Edmodo?

[Robert]

1) will the teacher believe me that it was not me who posted that nasty comment to him?
More than likely yes. It is not uncommon for facebook accounts get hacked and nobody is ever really hurt mentally by it.
2) will we eventually find out who posted that comment and hacked into my profile, work, and etc.?
Unless the person brags about at your school, then more than likely not.
3) does the teacher hate me now for something I did not do?
Informing the teacher was probably the right thing to do. Most people don't fret over things if you explain the situation
4) will the teacher still give me respect?
The teacher probably won't even care enough to change his opinion of you.
5) will I have to talk to the priciple?
Depends on how they take it. If they do talk to you, then it will probably be to hear your side of the story and just forget it ever happened.
6) is this something that I should be worried about?
Not even the slightest
7) will the school believe me cense I do tell the truth, I'm in 8th grade and a 14 year old female?
Again, they probably won't care.
9) and will u believe me
I would have to know a person to judge that for myself. Some people are attention grabbers and just want to under the spot light regardless of the means to get there.
10) would u guys hate me for something I did not do?
Of course not. A few words on the internet mean nothing.