What is the cause of yellow ball on inside of cheek after wisdom tooth removal?

Hi,

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Firstly, I would like to appreciate you for the clearest picture (attachment removed to protect patient identity) you have attached to your complaint. Next, my question would be, how long has it been since you removed the wisdom tooth, and did you visit your dentist after seven days for suture removal in that area? As far as I have noticed in the picture you have sent, the region seems to be good and healing. The yellow substance stuck mostly looks like food debris locked around the socket (sometimes it could be the debris swirled around the suture thread in case it is removed by now). Try gargling with warm salt water to get rid of it. Vigorous gargling is not advisable when it is less than three days since you got it extracted. If you are unsuccessful in this, then I reckon you visit the dentist back for a review and get a saline flush in that region, or the dentist would manually remove the debris with a tweezer without affecting the healing gums.