No
You will not get a credit for that child even if you amend your 2020 return unless it was issued before your 2020 return was due including extensions.
According to the IRS:
"Each qualifying child you use for the CTC or ACTC must have the required SSN. If you have a qualifying child who does not have the required SSN, you cannot use the child to claim the CTC or ACTC on either your original or an amended 2020 return. The required SSN is one that is valid for employment and is issued before the due date of your 2020 return (including extensions)."
2020 PUB 972
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