RA 9048 allows these corrections:
You may carry out necessary corrective measures right away, go to the Local Civil Registrar and point out your issues. The more you are truthful, the more they are convinced that you are willing to correct the matter at hand.
They may require you to produce Affidavits as attachment (The usual stuffs) for Correction of clerical or typographical errors in an entry in civil registry documents, except corrections involving the change in sex, age, nationality and status of a person.
You may be required to execute Affidavit of Acknowledgement/ Affidavit of Admission of Paternity.
(A clerical or typographical error refers to an obvious mistake committed in clerical work, either in writing, copying, transcribing, or typing an entry in the civil register that is harmless and innocuous, such as a misspelled name or misspelled place of birth and the like, and can be corrected or changed only by reference to other existing record or records.)
The point being, GO there now and ask politely.