I'm a frequent bodywork client and I have often had flashbacks while being massaged. Dealing with them in therapy has been helpful to making them tolerable and bodywork has been healing to me in return. Flashbacks are not so much a problem when you can learn to be okay with them, and then they reduce in frequency and intensity. I think you can get past this.

Have you read Bessel van der Kolk's book The Body Keeps the Score? Many body-based therapies are more helpful than therapy for many people.