Hello and welcome to HCM. Thank you for your query. Yes, the penicillin injection is much better than the oral route phenoxymethylpenicillin. The injection form given by the intramuscular route is the recommended route of administration of penicillin. The regimen approved is as follows: -Primary or secondary syphillis: A single dose of intramuscular benzathine penicillin G (2.4 million units) injection -Latent phase: If in the early stages, a single dose of intramuscular benzathine penicillin G (2.4 million units) injection -Latent phase: But in the later stages, A single dose of intramuscular benzathine penicillin G injections (2.4 million units) is given three times, once every week From the dosage that you have taken, it appears that you are experiencing a response, which is good. I would recommend you to continue the same dosage and advise for another 3-5 days at the least. Only if you do not experience a complete regression of your symptoms, should you opt for the intramuscular (injection) option. I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications at: http://doctor.healthcaremagic.com/doctors/dr-shoaib-khan/64581 . I would gladly help you. Best wishes.