I don’t think it is a reaction to
ciprofloxacin, but could be an aggravation of the persisting
infection. If it were a allergic reaction to the medicine it would be generalized, rather than local. If localized reaction is present that should be the site of injection. As you are on oral medication this is also not possible.
The most frequent side effects of ciprofloxacin include nausea, vomiting, diarrhea, abdominal pain, rash, headache, and restlessness.