This is most likely a herpes type one lesion. At least one of the lesions clearly looks like it. These are common. So you might want to rule this possibility out with your doctor.
It is not harmful, generally speaking.
It is caused by a virus.
Typically referred to as a "cold sore." This is since when someone is run down they often notice these outbreaks.
It is generally a self limited condition.
However, it can be contagious, even though most adults have already been exposed. [probably about 90% of everyone]. These do seem to appear more with stress, but most people do not have outbreaks. Stress is not a cause, but might temporarily lower you immune status and allow the virus to express itself.
Show this to your doctor.
If you wanted to confirm the type one virus, this could be swabbed before it goes away, which it will.
Apthous ulcer is a non specific term, which can refer to an entire cluster of disorders. They are idiopathic, cause unknown. There is a large differential diagnosis, and the other possibilities are not harmless, so even though apthous ulcers are harmless, there needs to be a close exam, under magnification to make sure of the diagnosis.
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Let me, Dr.
Thomas, know if you have more questions.
Double board certified US doctor.
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