The doctor you saw probably knew it was an allergic reaction to the dye. But ask your oncologist just in case as they are specialised. What you’re going through is scary and frustrating. I think everyone just says “I’m not a doctor” because no one wants to give you bad advice. Good luck on Monday, and remember that they have to tell you all that could possibly go wrong during treatment. Doesn’t mean it actually will. And google is not your friend when it comes to this illness as everyone’s experience is so different. For example, when I first thought I was sick, I read lots of stuff about how painful and terrible an oral biopsy was, but it didn’t bother me at all. I read how terrible an mri was, but I took medication to ease my anxiety and was fine during the scan. Just because someone else finds something intolerable doesn’t mean you will. I know you want to be prepared, but try not to read too much about other people’s opinions as they may end up needlessly scaring you even more.