Chocolate Lab 1yr Old. On One Side Of His Tongue Underneath Is Swollen, He Keeps Scratching And Rubbing That Side Of His Face On The Carpet/sofa. And Drooling A Lot On That Oneside. What Could It Be?

I have a 1 yr old lab. On one side of his tongue underneath, it is swollen. He is drooling a lot on that side, and rubbing, itching it as well. His behavior is normal and appetite is good. When we feed him, it is clear that the tongue is bothering him.