What can be done for a sore in the mouth?

Probably little. Generally these small ulcers are painful and we do not know the cause, but they clear up in about a week. On the other hand they may be due to herpes simplex virus, syphilis can produce mouth ulcers, as can coxsackie virus. Without seeing it and having more information the best advice is that if it persists, have it seen by your primary care doctor.

Related Questions

What can be done for sore mouth ulcers?

Mouth sores. It would be good to have your dentist take a look at the lesions to diagnose exactly what they are. Generally they last 7-10 days. Short term you can apply a over the counter ointment for canker sores/ulcers to numb it. It could be viral or bacterial or even from trauma or stress. Read more...
Topical numbing. First, there are many causes for mouth ulcers. These range from unknown through allergies, hot/spicy food or other things to cancer. If an ulcer has been present for more than two weeks it needs to be checked by a dentist. If ulcers come and go frequently then it may be possible to determine the cause and treat them. If they appear seldom and heal quickly then a toical anesthetic would help. Read more...