scout cocoa has a pump under her chin by her mouth, she use to get pimples when she was younger and you could pop them, but this one is about the size of a quarter and is really hard, she was at my older daughters for 2 days and came back with this, she did not have it before this and it cannot be squeezed and dosn't bother her otherwise.
I am not an expert by anymeans when it comes to this stuff but, I did have a dog that had this happen to him as well. He had a very large hard absess underneath his chin like you were describing. I took him to the vet and I was informed that what had happened was a thorn of some sort got loged into his skin while he was out playing and formed this absess. They ended up having to drain it but afterwards he was perfectley fine. He just needed some medication afterward and some extra tlc. I don't know if this helps or not but good luck :)
***Edited By: duckfan on 12/5/2005 6:06:45 PM*** Reason: made some mistakes had to fix