My dog is a 4.5 year old Beagle mix that I've had for almost 4 years now. He has always had pretty bad front looking teeth (missing one, some are chipped). He's a rescue from a hunting farm and vet said his teeth are fine during the last visit in May. Recently a red bump has grown above one of the front teeth and in between the tooth next to it and the bump is red and soft to the touch. He doesn't cry or whine when I touch it and his eating habits haven't changed. He still chews on his toys and eats bones so I'm guessing it doesn't cause much pain. I sent a picture to a friend who's a pet groomer and she said it looks like a canker sore that she's seen before (I'll post it when I get to my computer, on my phone now). Has anyone had their dog have a canker sore and did you go to the vet? I'm thinking about just waiting until his yearly visit in May unless he shows signs of being in pain. Thoughts?

EDIT: PHOTO http://i.imgur.com/ZY0f2yX.jpg