The majority of sudden blood pockets inside the mouth are caused by accidental bites while chewing or by eating hard foods that accidentally pinch the mucosa. Blood packets, also called blood blisters, are submucosal hematomas, where small blood vessels in the submucosa rupture, causing blood to leak out and ambush beneath the mucosa. Once the blood blisters appear, do not take any measures to break them, generally to observe the main, in about 2 days will be slowly absorbed. However, if the blister progresses at a larger rate and does not stop or shrink, it should be treated in the hospital as soon as possible, requiring local blood extraction or disinfection of the mucosal surface and then picking and draining the blood from the blister.