If a mother gives her son up for adoption and then decides that she wants to raise him herself what's the time frame that she can take him back?

Before the relinquishment papers are signed.

Each state is a little different, but there's generally no "do-overs" once you sign those papers, and they make that VERY clear in the courtroom before you do sign away your parental rights.

The only exception to that is if you can prove coercion into signing those papers.

Please tell us more about your situation so that we can help you better.