What could a red, painless bump on my lip indicate?

A red, painless bump on your lip could be caused by a number of issues. A common cause of lip swelling that is typically painless is a mucocele - a harmless cyst filled with mucus due to a clogged salivary gland. Often times, these will improve on their own with time. Syphilis is a sexually transmitted disease which can cause painless sores around the mouth or genitals. If you are sexually active, consider discussing STD testing with your healthcare provider. Canker sores, STDs like herpes, pimples, and other inflammatory causes of swelling on and around the lips are typically painful. If the bump grows, changes appearance, or you have other concerns, it is a good idea to have it looked at by a healthcare provider for a proper evaluation.