Hello, I Had A Tb Test Done On Monday And

Hello, I had a tb test done on monday and I had the injection administered on a tattoo. Today, they rold me I was positive and that I needed a chest X-Ray done. Is that ok for them to inject it on a tattoo ? I read that it has to be done on a clear zone away from tattoos, hair, etc... I would like to know if they are trying to scam me for money through additional testing like a chest x-ray. Thank you for your help.