These might be dental abscesses
on a tooth that has penetrated into the pulp
or nerve. Normally the pressure from a tooth abscess
is initially painful due to the pressure build up of the infection
inside the tooth. Once the pressure breaks through the gum above the tooth, the pressure is released, the pain
goes away, and a little pimple-like lesion remains. This lesion acts like a vent for the still present infection. If you suspect this is the case, a visit tot he dentist
is needed to treat the decay and infection.
One other possibility is that it is a traumatic apthous ulcer. These can occur when the gum is abraded too harshly with a toothbrush
or some other trauma is received by the gum tissue. An apthous ulcer looks like a blister with a red border. They act and feel like canker sores and will heal on heir own in about two weeks. Unlike the draining abscess
above, apthous ulcers tend to be more painful than you describe.
I hope this helps. If you have any other concerns regarding this matter that I have not addressed, please let me know and I will get back to you with more information.
Sincerely, XXXXX XXXXX DDS