Following dental extractions, there is likely to be some discomfort, but this should subside within 24 hours and should respond well to painkillers. If persistent pain is occurring after this period, then there is a chance that you may have developed a post extraction infection. This is much more likely if you are a smoker.
It is important to arrange an appointment to see a dentist, as left untreated these can become quite painful. Treatment normally consists of stopping smoking, irrigation of the extraction site, placement of an antiseptic dressing and use of antibiotics.
Swelling after an extraction is entirely normal, and is the body's natural response. It should normally start to settle down within three days, but if it persists after this, then it is best to arrange an appointment.