Be careful-- you know the old saying, "What you say is what you are." You might have the Wicked Witch of the West for an art teacher, and still not be able to withdraw from her class.
Can you tell me whether what level of course this is? High school, for example, would be a different house and significator than a university course. (3rd vs. 9th.)
I've looked at both possibilities, and I don't think this will pan out for you, either way. I could be wrong: really it is up to your school administrators and course withdrawal rules.
You are represented by Saturn. The 3rd house is ruled by Mars; and the 9th house, by Venus. Venus also rules the fine arts. As an authority figure, your teacher might be a 10th house significator, also ruled by Mars and with Saturn placed there.
Venus is combust and has no essential dignity. Mars is in detriment in Libra. Saturn lacks essential dignity in Scorpio. Mostly these planets plus the moon have no contact are moving towards squares are oppositions, suggesting further tension. The moon is strong in Cancer, but we take off a few points for her 6th house location. The moon will move towards a trine with Saturn, but not till she has created more aggravation in the situation.
I wonder if your teacher's hands are tied by administrative school rules. If not, as a former teacher myself, I can say that sometimes a teacher just has to let the failing students fail, simply to be fair to the hard-working students who are putting in the effort.
So it looks like your best hope is to be nice to your teacher, regardless of what you think of her. Sort of like what mature people do to get along in life when they want something from someone else.