How long does it take a perianal abscess to drain? i had one opened last sunday and i'm still getting a fair amount of drainage on gauze pads today...

Periapical abscess: You can't get rid of the drainage completely unless you have the tooth removed or have it treated endodontically, (root canal therapy). Nothing else will keep the symptoms from recurring.

May need more: If its still draining pus, may need to be opened more. If the dressing is dry or foul smelling when you change it, it needs to be changed more often. Wash it out well too. Call your doctor for an exam i make sure it healing ok. If there is no fever or excess pain, monday is probably fine, otherwise may needs trip to the er. Hope this helps!