Allergic to cup?

I’ve tried a couple cups made from medical grade silicon but they all make me feel like there is a nest of fire ants in my lady bits. I noticed I developed a rash when I had a silicon watch strap too. I thought silicon was supposed to be hypoallergenic. Anyone else have this issue and were you able to fix it? I can’t use tampons at all and pads no matter what kind I get I can tolerate for a couple days before I have constant burning pain. Any tips?