What Causes Recurring, Painful Boils Around And Inside His Nostril That Ooze Fluid In A Teenager?

Gn my son is only 15 and he keeps having this reoccurring cluster of boils which looks like cold sore , around his nostril and it spread inside the nose . Which run a water like substance and it hurts. He was recommended micospec bv which clears it in a few day but it come back in a few month time same area always... plz help