I really agree that this is very sensitive material for you, but there will be ways for this to work out for you, it is a matter of finding them.

Talk to your T. It is great that they are connected with the school, because they will have access to things that someone outside it won't.
They will know best what to do, but I think Miguel'sMom has a great suggestion. Perhaps you could get the T to contact the teacher, hopefully without needing to mention you, and say that they have been approached by someone doing this class, who has had it bring up issues which are very traumatic or difficult or inappropriate for them to deal with in a class situation, especially one where there is not the support of a skilled professional T.
Being given questions beforehand, and time to go over them with your T to talk about things you can deal with in class is a great approach.

I am sure any good teacher who was told this would understand the problem, even if they had not realised it beforehand. If someone has not gone through major issues, they could easily not realise the triggering effect this process might have on some, so I do not fault them for wanting to do this. It will help a lot of people in their music.