I have a fever at night and want to ask for leave in class. How to write a short message?

Just call and say you have a fever and want to ask for leave. Most teachers will let you. If you don't think it's easy to say it on the phone, send a text message to write down your actual situation, but pay attention to your tone and respect, such as writing teacher first, hello.

I hope you get better and drink more water. . . .