What can happen is that the nerve inside a tooth can die and abscess
leading to drainage into the gums which creates the gum boil
. It might bleed and can be purulent (pus releasing) or not. The other situation is if there is a localized area of severe periodontitis (gum disease). That can also result in a gum boil. The dentist will check out the area, take an xray and be able to tell you what can be done, either possibly a root canal ,deep scaling/curettage, extraction, referral, etc.