Got curious and found this - lots more out there, but this one seemed most helpful and more detailed than most. Most everything here and elsewhere mentions dehydration as one of the most likely causes!?

. . . feel better!
Originally Posted by WurlyLox
thanks the the link!

i got throught to the doctor's office and made an appointment. i was told alot of the stuff in the article! because i dont have a fever or any other syptoms that could indicate an infection i was told i should be able to wait until the appointment. i should continue with drinking warm liquids, gargling with salt water, and take and antiflammation medicine. if it gets worst i am to go to the er.

its really scary when it happened because i never knew your uvula could look like that. its kinda gross.