I had a small tear that had a lot of blood when I finally managed to take a crap after several days of not going... Is it actually IN the stool, or is it just coming from her bum area?
Does she have haemorrhoids? If so one of them might have ruptured - not a big deal, just painful, she can get treatment over the counter from a Pharmacy... Otherwise it could literally just be a tear - using a little bit of sudocreme or salt water (just something to keep it clean and help heal it) can help - I found it pretty painful to go for a wee or poo for a couple of days after it happened.
xx