What Bit Me?

I'm honestly asking. After googling my symptoms I decided I was bitten by a brown recluse spider, then promptly found out that these don't live in Australia. It's almost been a month and it's still not completely gone! 

I unfortunately missed the few days because it started as pretty innocuous red ring that I woke up with after a big night out. It sort of looked (and felt) like a burn to start with and I decided to start taking photos after it blistered up. 

When I was younger I was bitten by a white tail spider that was in our letterbox and my mum tells me it was a lot worse than this so I'm too worried about loosing my finger anymore. I'd still be really interested to know what it was!