Small bumps and lumps like this one are usually just small infections in the skin such as folliculitis or a small abscess
. This occurs when bacteria get into a hair follicle, get trapped and grow. The body fights it off by bringing white blood cells into the area. A small bump forms which becomes red, inflamed, and usually painful. I am surprised that this thing isn't hurting you. If it is a small abscess or infected follicle, then you should place a hot compress on it so that it can come to a head and drain more easily.
To make sure that this doesn't represent a bad infection that would require drainage, or something else entirely, you should show it to a doctor
. I suggest that you schedule an appointment with your primary care physician
. He or she can take a close look at this lesion and determine what needs to be done. Your doctor will either decide to do nothing and have you just put hot compresses on it, prescribe an antibiotic cream, or lance it and drain any puss inside. If your doctor thinks this thing is something else entirely, then you may need a biopsy (very unlikely). Good luck, I hope it gets better.