It's hard to think of how this would happen under normal circumstances. I can think of a couple of other situations. If she had been sunburned recently, and had peeling skin in that area, sometimes the skin is very tender. If some of the skin came off in the shower, it may have peeled off too many layers (especially if she had a severe sunburn) and it could have bled a bit in the shower....especially if she was picking at it or peeled it herself, which is a temptation when one has had a sunburn! Also, if she used a loofah or wash cloth, and had very sensitive skin, perhaps it opened up a weakened area (maybe, again, for a similar reason, if she'd had a recent sunburn or something) and there was a bit of blood seeping there.

I think this scenario would be very unusual. Hopefully it ended very quickly for her and she was okay after that!

Take care,
ErinBear