What Causes Numbness In Face?

I just read another person's question which was similiar to mine but I am not using paxil as she was. Mostly my upper lip goes numb...then it follows to the lower lip and nose. My face...mostly lip area also is contorting... sort of a pucker after eating a lemon...I have no control over it. Why is this happening? It has happened several times over the last 10 years. The first time was after an orgasm.... but today was during folding laundry. I am 24 years old... pretty healthy... not on any medication. Thank you!