Hello. I think the swollen testicle and the Ciprofloxacin are unrelated. I think that he possibly has something else going on. I think it would be important to perform and ultrasound of his testicle to see exactly what is causing the swelling. Swelling of the testicle can be an emergency if it is extremely painful. This is called a torsion. In this case he should be seen immediately. However, if it is not painful and is just swollen, it may be due to something else such as enlarged veins or a pocket of fluid. Either way, have it examined and continue the Ciprofloxacin until you are seen.