knot near throat??

I was wondering if anyone would have any idea why my cat has this round knot near her throat almost where a human would have a lymph node (sp?). It just all of a sudden appeared. I had another cat not long ago that seemed to have the same kind of knot on her side and the next day it seemed to have popped so I figured it was some sort of boil. Wondering if this is the same thing?

Is it kind of under her jawline? Zoey has one too
It popped up back in October, I took her to the vet and they aspirated it and determined it was a swollen lymph node. It was small about the size of a small gumball. They gave her medication but she only took a weeks worth of it because she started having diarrhea and throwing up because of the medication. It went down a lot but now sort of stayed at the same size. It's still there and its been like 5 months. Since her behaviour hasnt changed at all I have not been that concerned about it but when she goes in for her shots next month I will mention it and see if the vet is concerned. You may want to at least call the vet to find out if they think you should bring her in. If it pops that sounds more like an abcess rather than a swollen node.

Yes that is exactly where it is and about that size too. She is eating and active so I will wait another day or two and see if it decreases if not I will take her in. Thanks for the info.