How Can a Swollen Lymph Node In The Neck Of A Child Be Treated?

My 9 month old Great Dane has swollen glands under her jaw, at the front of her neck. The right one would be about the size of a ping-pong ball, and the left one is smaller, but still swollen. She has had a decrease in appetite, but still is eating some. Her bowel movements are firm and solid and a good amount in a mustardy brown colour. Her nose is warm and wet. Her big lips are warm and wet as well. She will still play with our other dogs. She has coughed twice today that we ve noticed, and each was just as though she had something in her mouth she wanted out. She also sneezed a couple of times today that we ve noticed. Her saliva is normal amount (lots for danes with giant lips) Thoughts?