Maybe come up with questions about the social anxiety like ways to cope, how she usually treats people with it, etc? Maybe reading about it will spark questions you want to ask?
I have a list that I haven't even gotten to. My T. knows it bothers me but she keeps going deep on things I bring up and then, poof, the 50 minutes is over. And, I keep adding to the list. I am learning how much my mother's emotional neglect affected me, my relationships, friends, vulnerability, etc. And, then I have concerns about my kids.