Diagnosed with secondary syphilis, primarily i received erythromycin for 7 days than passed to doxycycline this is my 13th day, the symptoms healed mostly but i can still see some in my mouth and on my glans. is this normal?

Syphilis treatment: Why not long-acting penicillin? It's the treatment or choice world-wide, unless severe penicillin allergy. Some syphilis is resistant to erythromycin and related drugs, very common throughout Europe. However, doxycycline is effective if taken reliably for 2 weeks (100 mg twice daily). Symptoms may take longer to clear up, however. If you remain uncertain, check back with your doctor.