Tea Tree Oil is my top tip, otherwise...
1) Poke it with a pin to open it up a bit
2) Get a small plastic bottle (eg a 330ml coke bottle) and a really cold cloth (a face washer or something that will cover the bottle, soaked in ice water), and a bowl of piping hot water
3) Dunk the bottle in the hot water, stick the opening over the blind pimple and 'seal' it (ie press it into your skin), then really quickly, throw the cold cloth over the bottle and watch it shrink. The warm air in the bottle contracts with the application of the cold cloth and it should suck your skin up into the neck of the bottle, and if done correctly, will draw most of the gunk out of the pimple
It's quick and easy once you work out how it's meant to go, then once you've drawn out as much as you can (you can repeat the process as many times as you like), dab it with tea tree oil or similar and see how it goes in a few days