A small white bump on a person's gum is most often due to an injury of the gum or is a canker sore; however, in rare cases the bump could be due to an abscess in the area or oral cancer, according to MedicineNet. Since the bump may be due to a serious cause, people should contact a health care provider with their concerns.
As noted by MedlinePlus, a canker sore is a type of mouth ulcer that can be white or yellow, cause pain and usually doesn't require medical intervention to heal. These sores may occur due to trauma in the mouth, hormonal changes, vitamin deficiencies, allergies or stress. Oral cancer, however, is more serious, usually requires a biopsy and will be treated according to what caused the issue, according to Merck.