The cotton after wisdom tooth extraction can generally be removed in about 30-40 minutes, after the removal of wisdom tooth extraction wound will remain, the wound will have blood seepage, the application of a cotton ball or cotton roll pressed on the wound will be the patient bite tightly, this will play the effect of pressure to stop bleeding. Generally speaking, the initial blood clot will be formed in about 30 minutes after the extraction, and no more blood will be leaked out at this time, so the time for pressure to stop bleeding is about 30-40 minutes. These are to avoid irritating the wound.