What could cause ocassional red bumps on my tongue edge?

[itac]

See pictures I uploaded with black arrows that point to the 2 red bumps I usually get when I have an "outbreak":
https://imgur.com/a/PX9J5

I can't really feel them in my mouth, there is no pain involved, it's only when I open my mouth and see them it kind of bothers me as it makes me wonder what causes these red bumps. I noticed it few months ago, it seem to come and go every few weeks.

I asked a couple general doctors and one infectious disease doctors I saw and they couldn't tell what it is.

Could it be caused by some virus like hpv that I could have gotten from performing oral sex on a girl? Or any other potential virus? I did get tested for all general STDs, so don't think this is caused by bacteria? Also, could it be an early sign for oral cancer? Should I see an ENT doctor for this? Does anyone else have this or know what this medical condition is called or caused by?

Please advise.

Thanks!