What will the teacher do?

[Max]

1) Take a deep breath
Ok, now that you have assessed the situation this is to answer your questions:
1)The school will not enact unless they are alerted or told about the incident in which they will take both sides of the story, in your case your story, then they will 99% of the chance believe you.
2) If you are a good student with no "bad cloud over your head" then the teacher should understand and believe your statement that you were hacked and you didn't write the explicit and far-fetched words stated above.
3) Most likely he doesn't hate you, I don't think he will hate you if you confront him with your facts and or information that you were sleep and unaware of this happening.
4) As stated above in my sentences, your teacher should believe you, but remember to confront him first thing in the morning about the situation and if he believes you then he will have it addressed to the school in which they should track and help avoid the situation.
5) Yes you should confront the principal AFTER consulting with the teacher about this situation and it should help you as long as the information giving above about you being a good student is true, not saying that you are lying, but falsifying information is easily done now a days.
I hope I helped you solve your dilemma and I hope whoever did it is brought to justice.