My LO is 3+mo and she is having this white smelly stuff at her neck area. Have been washing it daily but it's coming back every 2-3 days. Any advice on how to solve it? Thank you in advance;)

I placed a soft hankerchief when feeding incase any milk drips to her neck. After feed I will use damp cloth to wipe her neck and pat dry. Her fold of skin will tend to trap dirt and milk and slowly when she learns and knows how to lift her head then problem will be solved and not that frequent.