Sometimes we tell people things and it intensifies the emotions, and leads us to things we would rather not have happen. 20 years is quite a lot, but don't let one time of caving in break that.

As far as being terrified.....that's actually a good thing.... it's something so deep and intense that it scares you. and it could scare you into not cutting ever again. So yes talk about it anyway, it will be hard, but it makes us stronger when we do.