Monique will probably weigh in on this, but I looked at the private exchange we had on this part of the translation, and she assured me that's really what it says, literally, "so that the uvula fell off of this little one." The sense, as I gather it, is that Jesus was so chaste and pure, he wouldn't suckle on Mary's teats, and as a consequence his throat became inflamed or parched, either from malnourishment or underfeeding, causing the dangly bit to wither away.