agreed. If you parents dont get involved then they wont take you seriously. Depending on how your school is an apology letter might help abit.You'll need to drag your parents (Or guardians) into it, as Admin normally don't listen to the students, if they can convince them it was self defense etc you may have a chance
And i really dont think putting someone in a headlock is self defence....
But you could have avioded everything if you just kept your cool and had been smart. You knew that you were on probation, and from the admins piont of view they have givin you many chances. You blew it, not once but three times.