Can a tooth infection spread to your brain?

Yes: A very remote possibility but a possibility. This is why an abcessed tooth is a serious situation. There have been documentation that a tooth abcess was the source of a brain abcess and death. The infection can travel to other areas of the body or organs. The infection can be controlled and the tooth can be treated to eliminate the site of infection. See your dentist.

Yes: Yes an abscess can spread. Upper tooth infections can spread to the brain; lower tooth infections can spread to the neck and strangle you or worse, go to your heart. Tooth decay can be very dangerous. See your dentist and have the tooth treated or removed asap.