I called the pediatrician this morning, and she said that I shouldn't worry about Vivienne's tongue problem until later this week. She said it could take 7-10 days to heal. If I'm not seeing improvement by the end of this week, she said that we should take Vivienne to an ENT.
She seemed slightly better today, but the healing process is slow going. I'll be glad when my little baby is back up to full speed.