Could be uveitis, but only a vet would be able to diagnose it for sure. How quickly did the eye change colour? Does Lilly squint or does the eye tear at all?
Do let us know what you find out! Fingers crossed that it's not a big deal.
"To close your eyes will not ease another's pain." ~ Chinese Proverb
“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler