Apple Watch band - colour fading

Hi,

I bought a series 4 watch less than a year ago, the watch band is a sports band light pink. Unfortunately it os discoloured on the outside (shades of green). Strangely, the colour is fading on the outside but intact on the inside. I dont put any products on my wrists or forearms.

I’ve taken in to the Apple Store where I bought it, their answer was that it wasn’t covered under the warranty, which was disappointing.

Any idea why the colour is fading on these ‘Light pink’ bands, and whether this is a reversible process?

thanks