my baby is 4 months old. her head slightly got flat on right side. what type of care I can take to get normal

A. Flat head in Babies is very common mostly on one side initially when the baby is not flipping on the sides in the first few months . b so because of the continuous pressure over the soft skull bones such flattening can be there . This will become normal by itself gradually when the skull grow in size and shape with age . No musturd seed pillow or any such kind of intervention like massage is required for the corrrction .