Nosocomi

Hello everybody! I am a second year nursing student. Yesterday, I decided to have a PPD test done to me by my colleague. He took the right dose (0.1ml) in an insuline syringe (10 units). Unfortunately, after he had injected the tuberculin solution, I discovered that the syringe was expired! He disinfected the injection site and injected the solution in intradermal until the skin formed a papule. After he had finished he pressed it using a bit of cotton until the papule became larger. Today, I discovered that the site felt itchy and the papule measured 1cm or less! Is it a reliable result, considering how he did it. Can an expired syringe and pressing the tuberculin injection site yield a false positive ? Has anyone else had a positive ppd test and what was the outcome ? Thank you in advance.