A calamine lotion baby stain need to be treated as soon as possible because it is a tricky substance the seeps into clothing and sticks to the fabric.
Unfortunately, if the stain has been sitting for a while, you may never be able to get the stain out now.
However, for future reference, if calamine lotion gets on your baby's clothes again, immediately apply glycerin and dish washing liquid to the stain and let it sit for 30 minutes.
Launder as usual.

