Have Cat Questions? Ask a Cat Vet Online.
Some pigmentary changes are normal as the cat comes into adulthood. It's much like babies that are born with blue eyes. You won't know their true eye color until they are around 9 months of age.
I would have the vet take a look at it at your next appointment but if they did and didn't see a problem, I would not worry to much.
Let me know if you have more questions about this.
Feel free to post a pic. Just cut and paste it into a new reply.
Let us know if you need help with this.