Use antibiotic and. Moist heat over the area involved.
Antibiotics and time. If you had the appropriate treatment for an abscess, it may just be a matter of time for the swelling and pain to resolve. If either root canal, extraction or periodontal treatment was completed, and you are likely on a systemic antibiotic, it can take up to a week or so for noticeable swelling to resolve. If this has already occurred, i recommend you contact the treating dentist for a follow-up.
Depends. Your question is a bit unclear since it doesn't state whether you have been treated or not. If you have not been treated then the underlying problem must be addressed and treated. If the abscess has been treated by either root canal, extraction, or an incision and drainage then you need the appropriate course of antibiotics, along with warm compresses and time.