For the last 3 weeks at least (most likely longer, but 3 weeks ago is when I first showed my mom) I have had a swollen looking spot on my back gum. The swelling is about half a cetimeter or less in diameter, reddish looking, and appears to be slightly transparent (though I cannot see anything inside).

It is underneath and slightly between the left mandibular canine and left lateral incisor. It is not right at the junction where the tooth and gum line meet, but a millimeter or two lower down, at the point where the upper and lower slopes of the jaw meet.

I have not had any feelings of pain or discomfort around those two teeth, nor have I experienced any pus taste in my mouth. The spot definitely was not there when I went to the dentist only 3 months ago.

What could this be? Abscess? Gun injury? I did accidentally aggravate my gum once when I was flossing between those two teeth.

Mom thought it might be an ulcer, but it definitely is not. She said it's nothing to worry about and, as I haven't been having any pain, I'm inclined to agree, but still a little uncertain.