2,114. A Stain on Skin But Not Clothes

Hilchos Issurei Biah 9:21

Let’s say that a stain was found only on the woman’s skin. If the stain is at belt level or lower, the woman is unclean; if she turned herself upside-down, then even a stain from her belt and up would render her unclean. This is because if the blood came from slaughtering an animal or from the butcher’s market, it would also have been found on her clothes. Since this blood was only found on the woman’s skin, she is unclean.

Hilchos Issurei Biah 9:22

Let’s say the woman has a wound – even one that’s scabbed over – that could open and bleed. If blood was found on her skin, she can attribute it to this wound. The same is true in all similar cases.