I had a lower molar extracted a week ago (sectioned but very decayed and root retained). Pain has been constant but since then (not absolute agony) and I have had a foul taste in my mouth so I suspected it was infected. Saw emergency dentist today and she put a eugenol dressing in so I am guessing she is treating is as alveolar osteitis but also started me on oral metronidazole. Would this be for a secondary infection or also for the AO?