My 2-year old son has, what appears to be a mass of tissue, behind the last molar on the upper left side of his mouth. The tissue itself appears to be healthy, it's the same pink as the rest of his gums but, behind the "mass" the area is a bit red, (maybe an emerging tooth?). 6 months to a year ago, my Son had an illness that caused him to have a severe case of thrush. It was at that time that I noticed a spot on his gum, (where the "mass" is now) that was purplish in color. His pediatrician said not to worry about it, it was most likely an emerging tooth but, now, there is this, "mass" that looks like a skin tag. What could this be?