I took 4 tablets of Azycin, but it does not help for syphilis what to do next?

Azycin is a macrolide antibiotic, a derivative of erythromycin. Its biological half-life is long and amounts to 2–4 days. The fact that you take the antibiotic only for 6 days does not mean that the treatment lasts so long, because the antibiotic will work in the body for about 5-10 days. Please note that the dosage and duration of treatment depends on the stage at which the disease was diagnosed. However, if you are concerned about the lack of action of the drug or the accuracy of its selection, it is best to talk to your doctor about it. It is difficult to assess this without knowing your medical records. I enclose a description of the preparation that you are taking: https://www.gdziepolek.pl/produkty/8460/azycyna-tabletki-powlekane/ulotka/87933