When must i see my doctor about a lump on my labia?

Lump on labia: You should see your gynecologist as soon as possible, as it may be an infection of labia or infected Bartholin's cyst, etc.

Cyst/polyp/scar: Any persistent mass that does not resolve within 7-10 days should be examined. This could be due to a variety of different conditions that should be evaluated by your gynecologist which may be related to previous trauma, delivery, infections, stds, or cysts, etc.