Hi officegirl
Your post isn't long-winded at all - (and it wouldn't matter if it was).
I am sorry to hear of the recent change to your health. You can certainly submit a change of circumstances request - and ask them to look at your daily living only. This will trigger a review.
I can't answer whether it's worth it. You say that you now need help for every task. As you have a neurological condition, this is going to be an ongoing issue, so I don't think there is any danger in losing your award. And anyway, you still have the arthritis - so the worst that is likely to happen is that your award stays the same. Look at the Guide to PIP Claims and Reviews amd see which questions you think you should now score higher and that will give you an idea about whether it is worth you putting in for a change of circumstances.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems