Sometimes you can get a dry socket. In other words the clot came out that was formed and it's exposing some bone Also when it is a rough extraction some bone fragments can come lose. No matter what the problem can be, you need to go back to the Dentist that extracted the tooth. Meanwhile, be careful of that area. No sucking on a straw or smoking is bad for trying to keep a blood clot in place. No aspirin. No slushing after brushing your teeth. The office should have given you some instructions to go by. Go back to the Dentist. It's not normal to have this much pain after 4 days of the extraction. Blossom25 EDDA with teaching Degree.