I have a boil under my armpit since awaking wednesday morning. I have seen a nurse and started a prescription of flucloxacillin 500mg 4 times a day since friday morning, therefore have taken 7 abx so far and have been taking paracetamol. The boil continues to harden, increase in size and has spread into the armpit crevice more, becoming more reddened and now recently there is a discolouration (yellowish) in the centre. I have started to apply a hot compress on the affected area to increase white blood cells. Would magnesium sulphate help to draw it out or should I make an appointment tomorrow (out of hours)? Very painful and wakes me up at night