Hi mama! Totally normal yan, especially pag may binder ka pa, the fold happens kasi the scar tissue is still fresh and movable talaga, lalo na pag umuupo ka or nag-bend. A few of us CS moms noticed the same thing around 10 days, pero as long as walang pain, redness, or discharge sa tahi mo, you're probably good! That said, since you're worried, best to mention it sa OB mo sa next check-up or kahit mag-call ka nalang just to be 100% sure, they can see it in person at mabigyan ka ng peace of mind, kasi bawat healing ay different talaga.