That is frustrating. Especially when someone close to you doesn't believe you, or reads you incorrectly. I can't think of a way that would make her stop asking you... But possibly you could tell her exactly what you're thinking? Like, "Mom, you've been asking me often the same question about what happened to my arm. It's been bothering me that you don't seem to believe me when I tell you the truth. I've been trying hard and doing well in my recovery. It would really mean a lot if you believed me and believed in me." Of course, maybe not those exact words but maybe just telling her something like that might make her listen to you. I hope this helps.