After getting a penicillin injection or taking other antibiotics for syphilis, you may have:
If you do have side effects, they typically only last about 24 hours.
Once you’ve completed your treatment, the antibiotics will kill the bacteria that cause syphilis and prevent any additional problems from occurring because of that particular case. But it’s important to understand that the treatment can’t reverse or heal damage.
Fever
Headaches
Joint or muscle pain
All of the above, plus nausea and chills