I love the design! I swear, I always turn my nose up at browns and neutrals when I'm designing my own soaps, but then I see someone on here do a brown/neutral design and I'm struck with awe!
I think you'll find in a few days the whole cut surface will begin to discolor as well (although sometimes discoloration can be splotchy). By the time it's cured you shouldn't see a difference. If you were to cut into the cured discolored bar though, you would see the inside would still be a lighter color. It's just the surfaces exposed to oxygen that turn.
Although, that being said, I have had a few loaves that have only discolored on the outside (due to fragrance as well)...it's very strange and I can't explain why or how it happened...but I don't necessarily think it looks bad either way!