What should I (30M) do about a friend (25F) that says I ruined her life?

So I have a friend that a few months into the friendship told me that she’d like to learn to skate. This was a topic she brought up after I told her I was a snowboarder and longboarder. I told her I could teach her if she’d like and she said yes, and so the next few times we hungout that’s what she wanted to do. A few weeks later we were at the park and she skated off ahead of me (at a slow pace) and she fell and hurt her knee so I carried her to the car and took her home and advised her to ice it down. A few days later it was still swollen so I said she should go to a dr, idk if she did or not but she did go to PT a few times then quit instead of finishing the lessons. Fast forward a year to now, and she says she’s still in pain and shes blaming me for it still even tho I’ve apologized over and over. She says I’m responsible for giving her a life long injury and that it’s destroyed her and that it’s all my fault that I didn’t tell her she could get hurt and that she can’t go to the gym etc etc. she’s constantly held it over my head while I’ve tried to be a good friend since and idk what to do anymore. I care about her a lot but she says mean and hurtful things to me from time to time and says she does it because she wants me to feel the pain that she has. I still don’t even know if shes seen a dr because she never will tell me what’s wrong with it. I offered to pay for the PT lessons when she was taking them but she said no and then she’d forgive me and then a few months would go by and when Itd start to hurt again she’d blame me for it all over again.