What causes blood bubbles in the mouth?

Oral mucosa discomfort, or we eat relatively hard food, or there are residual roots in the mouth, residual crown stimulation, will cause oral mucosa bleeding bubbles. If the blood bubble is relatively small, we'd better not pick it, after a period of time will naturally slowly absorb healing. If the blood bubble is particularly large, even affecting our daily life. That should go to the hospital as soon as possible, ask professional stomatologist to puncture the blood bubble, squeeze out the blood and pus inside, and then locally apply some drugs that can promote mucosal recovery and healing, and also use some mouthwash, so that the blood bubble can heal.