Is this a possible abscess or something else?

Hello.

I have a possible gum swelling on one of my back molars (I think that's what it's called...). The swelling is next to the tooth on the inside gum. I'm unsure if it is an abscess, however, because there is no pain with it. I have no toothache, my gum doesn't hurt and the only "pain" I am having is when I press on the underside of my jaw but it's more discomfort than pain. I'm aged 24 and haven't had my wisdom teeth through yet.

The swelling is hard to see by myself because of the area it is located. When I feel it with my tongue, it feels similar to how a "jelly blister" feels on the foot.

Could this possibly be an ulcer or a cyst or do you think it's an abscess? I have had abscesses before during my early teens and had the teeth extracted and I had really excruciating pain when I had them before which I don't have this time.

I'm not registered with a dentist here yet and can't see an emergency one for a while.

Please help.