If I entered the country illegally back in 1993, can my US citizen son help me get my green card?
Your son must be a minimum of 21 years old in order to file a petition for alien relative on your behalf, immediate relative category, parent of US Citizen 21 years old or over.
The fact that your son is a United States Citizen and has the right to petition for an Immigrant Visa on behalf of his parent does not guarantee the issuance of an Immigrant Visa. The parent is still subject to being admissible and not being inadmissible in accordance with section 212 of the Immigration and Nationality Act.
Illegal presence in the United States for a period over a one (1) year brings a sanction of 10 years during which the foreign citizen can not be issued an Immigrant or Non-immigrant Visa until the 10 year sanction period has elapsed. The 10 years sanction bar is not triggered until the foreign citizen leaves the United States territory to attend an Immigrant Consular Visa interview.
The illegal presence bar of inadmissibility has a waiver that allows foreign citizens who have qualifying relatives in the degree of parents or spouses to file a waiver using the form I-601 that is based on extreme hardship to the qualifying relative. Only the relatives in the degree of parents or spouses qualify for this type of waiver, children do not qualify.
Therefore, because you have been illegally present in the United States for a period over one year, you will be subjected to the 10 year bar of inadmissibility, and your US Citizen born son (the petitioner) will not be able to qualify as a qualified relative to file and obtain a waiver based on Extreme Hardship.
Because you have not been inspected and admitted by an Immigration Officer at the port of entry, and because it appears you do not have a petition for alien relative or a labor certification filed with the service or the Department of Labor before April 30/2001 (Expiration of the Life Act), you can not adjust your status in the United States pursuant to section 245 (i) of the Act, that permits parents or spouses or children of US Citizen to apply for Permanent Resident Status in the United States as immediate relatives without having to pursue the Department of State Immigrant Consular Visa Process that demands the Foreign Citizen to attend a Consular interview to obtain an Immigrant Visa, and if the Foreign Citizen is present in the United States, implies leaving the United States territory to attend the Consular Visa Interview, triggering the 10 years bar upon exiting the United States Territory.