Do as karmabum says and see a doctor, I'm sure its probably nothing to worry about but best get it checked out. It could very well be a sebaceous cist, I had one on my cheek, although initially I was worried it was a very fast operation to remove it and you can hardly see the scar now.
I agree with both the above. If the doctor recommends removing it - have it done. The worst bit is the local anaesthetic injection, the rest is a doddle and you will be so pleased to be rid of it.
Go and ask your doctor! It could be anything, and without seeing it how could anyone possibly answer you? It's probably a small papilloma (wart) or a blocked sebacious duct. You don't mention whether it hurts, what colour it is, how big it is or anything so get a proper medical opinion from someone qualified who can actually look at it!