We went to the vet today, and told her that the bumpy has gotten way bigger since Thursday. And she agreed, and took Kahlua to have some other vets look at her, and their conclusion is that she most likely has an infection. So they took the safe route and gave her some Clavamox, to take for 2 weeks. If the bump doesn't go away or at the very least look smaller in that amount of time, they'll probably have to open it up. :( But at least we're on the road to figuring out what it is! I'm very optimistic that it's an infection, and not something bad, and the vet agreed that because of her young age it's probably nothing too serious.
So thanks to all for your support! We both feel SO MUCH BETTER now!!!! And I'm sure Kahlua will too, once that bumpy goes away!