My Grandmother used to tell about her experience with arthritis – she said her doctor told her there was nothing to do except take aspirin and exercise, so she kept on typing. (Remember those old Royal typewriters – you had to hit the keys hard to raise the carriage.)
She said it hurt so much that she had tears running down her face most of the day, but after a while the “treatment” worked. When she was well past 90 she could still do needlework.

I think if she’d had arnica rub her cure would have been far less painful.

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