@aksharkhat, I use Johnson’s baby powder I always either apply Aquaphor diaper cream or Desitin diaper cream and then put the powder on top of one of the diaper creams and it helps. My son has very sensitive skin so he gets rashes easily so I’m constantly letting him air out and using diaper creams and powder on his bottom.
Take your baby to the doctor, let your baby air out after a bath, and in between diaper changes, and use lots of diaper cream, and baby powder. Hope this helps!