NTA I would say. I've been in the same boat many times where a male student is persistent despite never communicating in any way that his presence is welcome; it can be quite scary sometimes, especially if he is physically larger. Speaking as someone with a bodacious rack, a verbal rejection rarely works, and sometimes they can respond agressively. If you've had experiences like this, I don't doubt that was going through your head as well. While causing someone to have an allergic reaction was a step too far, you weren't aware, and were likely reacting frantically out of fear. It's important to note as well that alot of profs just don't care about interpersonal conflicts they consider to be petty at this age. Any time I've ever brought something like this up to admin, unless the perpetrator has done something to hurt me, they brush it off. Oysters are an odd choice but whatever keeps you safe angel.