You must now WAIT for the IRS to process the return you have filed ... the ball is in their court right now.
They MAY reject the return and mail it back for a correction... if so make it and remail or efile it.
BUT IF ... they remove the child due to an incorrect SS# then they will recalculate the return and send you the new refund amount or a balance due notice. At that time you will know how to amend the return. Until you know what they will do you cannot do anything yourself.