Click vvvvv
http://www.recoveryourlife.com/index.php?categoryid=91
You need to see your GP, if you can't feel when you poke it, that means you damaged nerves.
The article really covers more than I know, but... DON'T POT BLISTERS! It opens you up to all sorts of nasty infections.
Definitely either get to the A&E, or make an emergency appointment with your GP.