In the past few months, did you have a great deal of pain back there that shortly went away? A bump on the gum usually means a nearby tooth has had its nerve die and is trying to drain. It really needs to be seen to, or it can get infected. I'm the biggest coward when it comes to dentists, but this just happened to me beginning of the year. I loaded up my mp3 with funny radio shows and soothing chant, and got on with it.
And now it's all in the past. Think how quickly a month goes by for you. Get it taken care of as soon as poss, and it will be over and done with and in your past, too.