quick question

I was cleaning 2 of my snake tubs so i put my male in with the female while i cleaned his tub reall quick, then i notice my female moving around with her tail pointing up i finished cleaning the males tub so i put him back and i noticed blood where the female was moving with her tail up.

any idea what i could of been or why?

Shed recently?

Sometimes stuck shed can cause a little bit of blood.

How much blood are we talking about?

not too recent like 2-3 weeks ago. a couple marks where she was moving while her tail was pointing up.