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Chancre After Penicillin Shot

I was exposed to STDs due to a terrible decision on April 5. The next day I went to the hospital and was given an assessment and received a course of antibiotics which included a penicillin shot for syphilis. Several days later a chancre appeared on the shaft of my penis.  Does this mean that the antibiotic shot did not work? or does it perhaps take a period of time to work? It's been 17 days since treatment already.  Thanks!
8 Responses
Avatar universal
It is probably unlikely to be syphilis. See a Dr for an exam.
Avatar universal
Thanks for the quick response.  I'm definitely going for a check up / follow up testing next week, but I wanted to ask if that's a possibility.  The antibiotics I was given were to prevent the onset of gonorrhea, chlamydia and syphilis.  The chancre that showed up matches the description of a syphilis chancre to a T:  A single, small and round sore, no pain or discomfort, some discharge at first (it no longer discharges).  I have not displayed any other symptoms or discomfort at all. Other than the unsightly sore, I feel great. I guess what i'm getting at goes back to the original question... can a sore still develop even after treatment? it was a single penicillin shot and I was not advised to go back for a follow up treatment (Dr. @ hospital said a single shot right after exposure should be more than sufficient).  
Avatar universal
Google a picture of syphilis sores. I would guess yours looks different
Avatar universal
Looks just like most of the pictures.  No matter, though. I'm still going to have it looked at... I just wanted to satisfy my curiosity and find out if a chancre can still develop after getting a penicillin shot 24 hours after exposure. Can this happen?
Avatar universal
Well anything is possible, just don't think it is likely.

What was your exposure?
Avatar universal
unprotected penetrative oral and anal sex after a night of drinking way too much and making the horrendous decision to have sex with someone I just met (still kicking myself over it).  My baseline status was clean prior to this encounter. I have been with only 1 monogamous partner for the last 5 years and I was screened and tested squeaky clean about 1 year ago. In case you're wondering, I am also taking nPEP in case of HIV exposure.
Avatar universal
Avatar universal
Not sure if an appearance of a Syphilis chancre is possible after only 7-8 days of exposure... especially after taking a Penicillin shot.

You need to go have the chancre looked at as soon as possible.
I wouldn't wait until next week if I was in your position.
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