You need to file a motion for scientific paternity testing. If you already have a case opened you can file the motion in that case.
Paternity by: Staff, FALDP
On the Florida Supreme Court's site, www.flcourts.org there are Supreme Court approved family law forms for pro se litigants. One of those is called:
Petition to Determine Paternity and for Related Relief - Form 12.983(a)
Since you were never married to the mother, in order to assert your paternal rights and have regular visitation with your son, you need a court order granting you visitation (timesharing).
Read the instructions on the form carefully. The instructions explain which other forms must also be filed. This information is not intended to replace legal advice. Please seek counsel if you need legal advice.