I'm pretty sure that the Social Workers lied to you when they told you that the mother tried to suffocate her baby with a pillow.
Social Workers are liars and kidnappers.

Please read the post that I made a couple of days ago.
This loving mother was accused of throwing her baby out of a window.
She was set up and lied about and it completely destroyed her.
Then her baby was adopted out to another mother.

https://steemit.com/familyprotection/@canadian-coconut/when-kidnapped-children-get-adopted-familyprotection-series-tammy-s-story

But you are right that you had better be careful not to be accused of something yourself over someone not understanding those birth marks. There are many stories of foster parents losing their own children because the Social Workers turn on them.
I would NEVER ever let those monsters into my home without a Court Order. Once you let them in, they will manipulate and twist everything that you say and do into an excuse to kidnap your children.