This might sound stupid, but....have you thought of switching mediums?
I mean, I don't know much about your case, but if holding a pencil becomes too painful.....what about finger painting?
I know that, for me, it's not always about doing something perfect. It's about doing SOMETHING, something that proves I'm still me - I'm myself, and I'm not defined by my RSD.

Hugs for you, too - your PT sounds like a wonderful source of encouragement. I'm glad you have someone like that in your corner.