When mouth ulcers appear after tooth extraction, most of them are ulcers caused by the eye of the needle at the injection site, and some patients have ulcers caused by the jaws or pliers accidentally touching the gums during tooth extraction, which are more fragile. In this case, you can use medications for ulcers, such as open-throat sword spray, stomatitis spray, watermelon cream spray, or you can apply a paste, such as furacilin paste. The ulcers are usually traumatic ulcers and will heal on their own in 7-14 days without applying any medication, so patients need not worry. Try to eat a light diet, keep the extraction site clean, and do not eat spicy and irritating food to prevent infection of the extraction site.