What Causes Swelling And White Discoloration Of Skin On The Lip?

The lower right side of my lip started swelling, the skin has a white color to it and throughout the night the swelling spread across my lower lip to the middle and then spread inside my mouth, still on my lower lip. Any suggestions? I don't think I've eaten anything that I was allergic to, even so an allergic reaction wouldn't last this long would it?