Alas, today, people in our class made the head teacher cry, and my heart hurts a little. ...

If you are a cadre, you can go directly to comfort. If you are not a class cadre, I suggest you bring a class cadre (usually dealing with your class teacher more) to comfort the teacher.

I suggest you go to her face to face, which will be more sincere and make the teacher feel more comfortable.

If you do send a text message, first explain your identity (the teacher may not remember your mobile phone number), then explain it according to today's situation (you must know the specific situation better than me), and then say that we are all children and are not sensible. I hope the teacher won't take it amiss. We also know that the teacher is also good for us. I hope the teacher will not give up on us and so on.