Can you move the 'bubble'?
Lymph nodes are present in your entire body, and even on your face. I have TMD, and I had to ask my doctor a few times while in, as I felt this lumpy thing in my cheek.. funny how it returns every now and then in the same place, but I can move it, and its not hard, more squishy. My doctor told me those are the two things to look for, as to not to worry about it. There are also large lymphnodes that are present where the jaw meets the neck-- the more you push on them they squish out their fluid and my disappear for a period before filling again.
Maybe its due to your body fighting some form of infection, hence your fever?
I would go see your family doctor just to make sure. If it is suspicious, they will let you know.
Seeing an oral surgeon is advised.