Swollen lips may be caused by allergic reactions, injuries, chapping or sunburn, infections, and cysts called mucoceles. The swelling comes from either inflammation or built-up fluid under the skin.

Podcaster Saron Olkaba’s viral TikTok, “Pigmented Contact Cheilitis,” has sparked a conversation about a lip reaction some people experience but may have never heard of: pigmented contact cheilitis, ...