This is wonderful news about Bumpy's recovery from scent sac surgery.
As for the scar color, I would just give the vet's tech a quick call and ask about the color.
If it continues to concern you after that, you might want to give the vet a call and ask about it.
A quick reminder.....
You are never being a pest when you call your vet with valid questions...
you are being an involved, concerned parent.
Thanks for the Bumpy good news update.