If this problem is known to other people in your class too, maybe one day you can get together with some classmates and let your teacher know about it? For example, at the end of a class one day you could politely go to your teacher and say something like:
'Miss, we are finding it a bit difficult to read your writing, if you don't mind can you please write a bit bigger and more spaced out'.
If you go with some classmates then your teacher will know that it's not just one person having the problem so it's more serious, and your teacher will hopefully not get offended when you let them know
