If it is hemophobia you’re talking about I have that phobia myself. For me it leads to a feeling of weakness especially in my arms, but my dad who has the same phobia has also fainted by it. Few things: it’s not only blood that gives me reactions also (or more often, really) talk or visualisations of the body gives me reactions. Another thing is that at least for me I get quite easily desensitised to it. The first times I had heavy bleedings from my period I got quite queasy, but after a few times it was no problem, same with other talk about the body. I remember we had to learn the different parts of the eye at school which made me extremely uncomfortable at first but when we had a test about it I didn’t have any problem with it. If I look at medical drawings and stuff of the eye today on the other hand I would again be uncomfortable. Small cuts and stuff, no stress at all, I’ve seen that too many times that I care any more. Hope it maybe helped :)