I have a hard and painful lump on my labia. what could it be?

Bartholin cyst,, abs: Cold be a Bartholin's cyst, or an infected sebaceous cyst. Sits baths may help. Also consult with your doctor, it may need to be removed, or drained.

Several things: This problem mandates a real-time (face-to-face) meeting with a doctor. A history has to be taken along with a examination as well as labs and other tests. Only after all this will his doctor be in a position to tell him what's wrong and what needs to be done to help him.