My dog has a growing, swollen lip bump with a puncture. What is it?

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question about Ellie. I see what you mean about the bump on her limp. I would expect that if it were an insect bite, it would have gone away by now, not gotten bigger. I'm wondering if that bump is a kind of growth (likely benign given her young age) or if it could be a cyst. Given that she has had it for over a month and it's getting bigger, this is something that needs to be checked out by a vet. Any suspicious bumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the bump to get a sample of its cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. Once the cause of the bump is diagnosed, the vet can discuss treatment options if needed. Give her vet a call to make her an appointment. I hope this helps!