The recommended therapy for prevention of syphilis in penicillin allergic persons is
doxycycline, 100 mg by mouth, twice daily
for 2 weeks. To verify that you did not get
syphilis you should have a blood test for syphilis both as you start therapy and upon completion. If the 1rst test is negative, the second one will be as well. At the end of therapy you can assume that you have prevented you infection and return to work.
Lesions can be subtle in women and might be missed.