An extraction is a surgical procedure and post-extraction instructions need to be followed strictly. Did you keep the pack with pressure on it for half an hour and then remove it? Sometimes, the blood clot gets dislodged because of things like spitting, sucking a liquid through a straw , not resting your mouth. If there is bleeding roll up a piece of sterilized gauze and cotton and place on it, bite hard , for 20 minutes , if bleeding stops fine if not go back to your dentist. Also slight amounts of bleeding is normal, you can swallow it don't spit. Pain is also expected after the anesthesia wears off . Best contact your dentist do not self medicate.