I have a large bump on my lower pubic area right above where my penis starts. I thought it might be an ingrown hair, but I haven't shaved in months.

Still possible. It is possible that you have a cyst or an abscess from an ingrown hair or a sweat gland. It is possible to develop a clogged skin poor, hair follicle, sweat gland without an infection. It will form a nodule that could possibly become infected later. If it bothers you, see your doctor sooner than later.