Blood blisters that keep showing up in the mouth are a possible symptom of mouth cancer. Most mouth cancers begin in the squamous cells that line the mouth. This type of cancer works into deeper tissues, often spreading to the lymph nodes, states the Better Health Channel from the State Government of Victoria.
Some of the risk factors for mouth cancer include smoking or the use of smokeless tobacco and heavy alcohol consumption. While a persistent blood blister in the mouth is enough reason to go to the doctor on its own, other signs of mouth cancer include a visible growth that might be painful; an ulcer that refuses to heal; loss of feeling anywhere in the mouth; difficulty swallowing and moving the tongue; issues with moving the jaw; slurred speech; sore gums; loose teeth; changes in taste; and swollen lymph glands, according to the Better Health Channel.
Because the mouth is so close to the lymph nodes in the neck, once the cancer starts to work its way into other tissues and finds the lymph nodes, it can access the body's bloodstream and lymphatic system. This allows metastasis, or spreading, to take place much more rapidly, notes the Better Health Channel.