Be careful about asking your child to tell you all about a traumatic event. Unlike normal every day memories, traumatic material gets recalled by reliving again the feelings, body sensations, smells, images, sounds, tastes, and sometimes thoughts at the time of the experience. Re-traumatization is probable if a child is asked to tell the trauma story without clear preparation for the process.
I have worked with many children who were expected to tell what happened to them to a therapist before they were ready. The result is complicated trauma, avoidance and denial of the material, and extreme dislike and mistrust of therapists. That is where the concept of “first, do no harm” goes off the rails. Don’t be afraid to question a therapist about how s/he plans to approach your child’s deep pain.