Lump Enlarged Lymphnodes or abscess?

I found a lump under Ponyo's neck about where an adam's apple would be. The lump is hard and actually feels much like a man's adam's apple but maybe a bit harder. She is still eating a lot, drinking plenty and is active. Ponyo will be going to the vet on Monday but I'm just worried about a few things.What should I be expecting when she goes to the vet? When is to young or small to go under anesthesia? And does an abscess feel different from an enlarged lymphnode?