Uneven skintone

Hello mommies, ask ko lang po of this is normal? uneven po yung skin ni baby s neck area. Nagka rashes po sya jan before pero nawala when we switched from Lactacyd to cetaphil. Pero nung natuyo po ung rashes ganyan na po sya uneven na ung skintone. Makinis nmn po ung area, uneven lng talaga, idk if mawawala din eventually eh. Thanks pi in advance.