While you can get a pimple on your lip line, you cannot get a pimple on your lips. A "pimple" on the lips is more likely a cold sore. If you're still unsure if the pimple on your lip line is really a pimple or if it could be a cold sore, here are a few key points to remember: Cold sores tingle or burn, and may become painful. Cold sores cause tiny, red blisters to form in a cluster. After several days, cold sore blisters will crust over.