Hi. My 15-year-old son was diagnosed with Hodgkin's Lymphoma in July. What I can tell you is that his swelling in his neck was the size of a golf ball and, as the weeks went by, the whole side of his neck enlarged. It was a hard, painless lump which didn't move when touched.

We waited six weeks from the time of going to the G.P. until we got the official diagnosis. In that time, I did a huge amount of research so the actual diagnosis didn't come as any real surprise.

What I can say to you is that if your swelling has decreased that seems like a very positive sign. With my son, the swelling only continued to grow. He had no pain from it. If your lump was painful then that could indicate other things less severe. 

Fingers crossed for you. Keep us posted. Hope your scan goes well.