How do you know if you have an abscessed tooth?

I currently have an abscessed tooth. I had horrible pains, so bad I almost went to the hospital. It almost felt like a serious migrane, the next day the pain was more concentrated to my back tooth. there was minor swelling around the tooth and my lymph gland was sore to the touch. Go to the dentist because the pain will go away and then come back even stronger in a few days. Good luck with it!!!

A tooth abscess or root abscess is pus enclosed in the tissues of the jaw bone at the tip of an infected tooth. Usually the abscess originates from a bacterial infection that has accumulated in the soft pulp of the tooth. Abscesses typically originate from dead pulp tissue, usually caused by untreated tooth decay, cracked teeth or extensive periodontal disease. A failed root canal treatment may also create a similar abscess. It may also develop from bacteria entering a tooth filling and multiplying. The pain is the body detecting that the microorganisms are present. A pus taste may also develop. There are three types of dental abscess. A gingival abscess that involves only the gum tissue, without affecting either the tooth or the periodontal ligament. A periapical abscess starts in the dental pulp. A periodontal abscess begins in the supporting bone and tissue structures of the teeth. (Wikipedia)