Re: last 3 fingers went numb....
You could have injured the nerve that comes down along the outside of the arm and serves those fingers. It can be injured from overuse or just plain pressure....I did the same thing making my wedding gown...spent so much time leaning on my elbows, hand sewing that it went numb.
so you can give it some time and see if it gets better on it's own.
But if it doesn't show signs of getting better fairly soon, have it checked out. If it gets worse(fingers don't want to work) then have it checked out ASAP. It could be from nerve damage anywhere from your wrist to your spine. It's not carpal tunnel as that involves different nerves but it could be cubital tunnel when it gets caught in the elbow area.
But numbness anywhere is always something to get checked out if it doesn't go away as the next step can be loss of use.....completely.
And arthritis rarely causes numbness....just pain. Just another thing to have checked out.