What Causes Numbness And Blisters On My Inner Lip?

I woke up one morning a few days ago and the inside of my bottom lip was slightly numb. Now it feels almost like I can feel a line right down the middle of the inside of my lip and now there's tiny little white bumps on the inside where it's numb, but I don't know if that's because I been rubbing it with my tongue and just irritating it or if its the cause of something more serious. I can still feel it though because it's not completely numb. Any idea what the cause could be?