Make an appointment to see a doctor urgently, or go to the ER.
You have an infection and it appears to be spreading. The boil may need to be lanced and drained, but it sounds like you need a course of antibiotics.
If the boil has no broken skin, you can apply a poultice to help to draw it to the surface. Magnesium Sulphate paste (this is a drawing ointment) can be purchased from the pharmacy.
Get medical attention urgently.