Sorry to hear about this, and it needs to be examined by a doctor
soon. While this could be many things, the fact that it is tender and has been there for several months is quite concerning to me. You leave out many details, such as your age, smoking or tobacco history, and other important details that would be necessary for full and appropriate treatment. Even without that, however, I can tell you that what you are describing is not normal and needs to be evaluated. Perhaps an ear nose and throat surgeon
(AKA ENT or otolaryngology-head and neck surgeon) is perhaps best suited to treat you, as almost their entire training is dedicated to diagnosing and treating lumps and bumps in the head and neck that should not be there. The surgeon that you see may be able to reassure you, or he or she may feel that further intervention or imaging is necessary. Most importantly, he or she will be able to ask more questions about how and when this showed up and if it has changed over time. Please speak with a doctor immediately about this concern so that you can be diagnosed and treated shortly.