Sorry to hear about your problem. There are many different things that this could be, and it is difficult to know exactly what this is without speaking with a doctor
. This is why i recommend discussing your concern with your doctor. Depending on your age, risk factors, and past medical history, this could be anything from a benign skin lesion (something as routine as a pimple or more complex like small cyst of skin and infectious debris), or something much more ominous. It is reassuring that this has not grown, but I am not sure what to make of the fact that it doesn't hurt. As different as it may sound, things that hurt are actually somewhat more likely to be less menacing, because of the fact that they are more likely to be infectious or something else caused or due to inflammation. When they don't hurt, your doctor may be more concerned about this being something more serious. As for the small red mark, there is certainly the possibility that this could be the sign of either trauma or some skin problem, potentially even something as serious as a cancer. Obviously, there are many different possibilities, and speaking with your doctor is the only way to know for sure. Please speak with your doctor.