Help needed...obscure child toe occurance!

[WittyTitle]

My DD (age 6) came home from school yesterday complaining of pain just underneath the front of her school shoe (court shoe). She had stupidly took off her socks during the day as she was hot, and as they are quite new shoes I just assumed it was a bit of rubbing, stuck a bandaid on and sent her to bed.
When we took the band aid off this morning there is what can only be described as a 'teenage style zit' on the top of her big toe and its a very angry looking pus filled one at that. Its the size of mars (well at least 5 mm across) and shes complaining of it being very painful, refusing to put any shoes or socks on.
So my question is....why the hell is there a pimple on her foot, how do I get rid of it, and do I pop it? What treatment do I give it????

THey didnt warn me of angry toe-zits in my antenatal classes!

Haha that last one made me roar.
It's getting much better, werr back to shoe-wearing and I think she had almost forgotten about it, DH came home and she went for maximum sympathy possible, turf"d! I got the usual disapproving glare whilst pretending to listen to a lecture on infections and all that jazz but when I pointed out she's fine he didn't seem to have a comeback.

As for the finger bandage advice ginger it sounds like a good idea for bigger injuries but I didnt want her seeking anymore sympathy that her monthly allowance, so we kept it to a minimum. It's uncovered and starting to heal,

So hooray to the ladies whose wonderful advice no doubt prevented gangrene and certain death! Thank you so much for all your help!