Gummy lump at back of mouth near where Wisdom Tooth should be... very painful

Hi, I have been having some trouble with a painful lump that has appeared in the last week at the back of my mouth on the bottom row of teeth, where my wisdom tooth SHOULD be. It has not appeared above the gum yet, or could be in the process of doing so - that was my original thoughts, that it was my Wisdom tooth coming through. But on closer inspection, that doesn't seem to be the case, and although it is in the same place where my wisdom tooth should be and is maybe connected, i can't feel the tooth, just this horrible very painful lump. It hurts to swallow and to eat on that side of my mouth, and is acheing all the time. Is this a wisdom tooth coming through or something else?! Thanks for any help.