Hello, 

            it could be an inflamed lymph node.They are indicators of a viral, bacrterial infection or disease.They usually resolve themselves fairly quickly aZZs the inflammation recedes,but if they should stay inflamed for a longer period then best to get it checked.Given that it has only been swollen for a short time,its early days to go rushing to a cancer site.Hope it resolves by itself in the next few weeks andin the meantime stop poking about with it, poor thing,

                                                                                              David