Just so I'm clear, I'm not looking for medical advice, I'm just seeing if anyone else that has been spiked by a Tarwhine (or any fish really) has had the sore stay around for a couple of weeks and sting when touched. Just want to see if that's normal or if some of the spike is maybe still in there causing it in which case I'd want to get it removed.

 Got done by a small flathead few years back. Same prob as you . Ended up finding a very small part of the spike in my finger. Same symptoms as you. I dug it out and healed in a week. Just painfully digging around with a needle 

If it is still giving you the business after a week I think you will find that you still have a bit of spine still in your finger joint.
Time to visit the doctor or emergency dept of your nearest hospital

it shouldn't be sore after 2 weeks, see your GP.

 Crayfish spine did a similar number on me recently. Just dig it out with a needle and disinfect. Good to go.

I'll have a go at it with a needle and see how I go.
I was told to soak it in hydrogen peroxide which could pull out whatever's in there on it's own, did that last night and nothing came out, but this morning a small hard thing almost like a big grain of sand came out, and it feels noticeably better.
Hoping that's all it was. Will try another peroxide soak again just to be sure. 

Did some digging with a pin and hit something hard, used some tweezers and got a very small, maybe 1mm long, bit of spine out. I didn't even notice it come out because of how small it was.
That's a relief. Good thing I didn't just leave it for it to potentially get infected and lose a finger. 
Thanks for the advice guys. I've learnt my lesson now, no more carelessly handling fish for me!

 if there is still any pain -bet bits still in there - ill put a case of beer on it

go to ED they will do a ultra sound

and confrim 

the secret is to nerve block the finger - then use a disposable gloves finger as a tourniquet to stop the bleeding to have a decent poke around to get it out

ask me how i know

at 3 weeks in ur finger u end up on intravenous drugs 

It still hurts a little bit but that's only when I really squeeze it. It hurts just about as much as I expect any open wound caused by digging around with a sharp pin would, so I think it's just that.
For now I'll let it heal over and then I'll give it another squeeze to see if it hurts. If it does I'll go down to the GP for an ultrasound. 

 Think I'm in the clear. After letting it heal up a little bit it doesn't hurt anymore. 
Thanks for the advice guys

Try some concrete !! That should

sort you out buddy !
cheers pirate !