What Could Strange, Flat Piece Of Pink Skin Protruding From Under The Tongue Of An Infant Be?

I just noticed that my 7 month old has this strange, flat piece of pink skin protruding from under the left side of his tongue. It s flat and round at the front, but can t see exactly where it originates because his tongue is short and flat. He doesn t cooperate long enough for me to move his tongue far enough out of the way to see it completely or clearly. We plan to call ped tomorrow, but cannot find any pictures online that look similar to what I am seeing in his mouth?