u/Full-Letterhead-6279

I experienced an MST event while deployed, it was reported and an investigation was completed, this was a decade ago. I started going to VA therapy for it in November 2025. My therapist does not want to diagnose me on paper but she says I do have PTSD from it.
I have the decision letter from the investigation still, and I’ll have a lay witness statement from someone who knew me before, during, and after it happened plus my personal statement. Could it be difficult to get a claim without diagnosis on paper?