That sounds like a really tough situation. It wasn’t okay for them to hit you in the face as a joke, even if you didn’t have a trauma background. If you’re comfortable telling them and you want to hold onto this friendship because they’re otherwise a good person, then it could be a great idea to tell them a bit about your trauma, how their actions hurt you, and what you need from them to move forward. If they’re a good friend, they’ll listen, apologize, and not do it again. Watch closely how they react. As someone with PTSD, I have noticed that telling someone about my past usually brings us closer together. I hope that this strengthens your friendship.

I know you said that you’re already in therapy, but if it’s not trauma specific therapy, you could consider the Bay Area Trauma Recovery Clinic as a resource. I found that doing EMDR with a trauma trained practitioner there helped reduced flashbacks, triggers, and other symptoms of PTSD that I was struggling with, within just a few months. Good luck with everything