Depend on how done
If just lanced, stabbed 2 drain, it may reseal the wound & remain or progress.
If cut open and a rrain inserted it may clear in 1-2 wks with proper antibiotics. If unroofed or the top layer of skin over the boil it needs daily or more frequent dressing changes of packing, and heal from the bottom up. This is the surest way of no recurrence &takes longer depending on how wide & deep the boil is.