Mouth Color Difference

Your lips (50 percent), tongue (40 percent), or entire mouth interior (10 percent) is a color not normally associated with your ancestry. (The player and GM should discuss color or choose randomly from https://www.random.org/colors/hex.) While not extremely noticeable or easy to explain away, this gives disadvantage on disguise attempts and Charisma (Persuasion) checks in subcultures that emphasize appearance such as nobility or military. This trait has no IE.

Real-world Examples

Cyanosis, Oral Thrush, Anemia, Addison Disease, Kaposi Sarcoma, Lichen Planus, Leukoplakia

Assistive Options

Eating fruit that matches a normative mouth color can help but wears off in 2d10 minutes. Lipstick can cover lip color differences but wears off while eating or exposure to liquids.

Magical Assistance

The Color Flesh cantrip can temporarily modify mouth color, but the target will not notice when it wears off.