Eponine's mouth drops open in sheer astonishment. She stares at Abigail without saying anything.
"Why?" She eventually says. It comes off more challenging than she means it to be.
"I mean, I ain't got nowt but the clothes I stand in. I can't give you nothing back for you to brush my hair. But you want to?"

Eponine swallows hard. She knows, at least this time, she doesn't deserve any kindness. Oh, but how lovely it feels... and how guilty she feels at the thought of it.

"I don't mind being alone, you know? It is lonely, but... but it's safe? Almost? No. I'm too stupid to know the right word. It ain't safe. Bad things happen to women like us when we are alone on a street. Women like us become bad... I'm bad."
Eponine grows quiet for a moment, and scuffs her heel in the dust.
"Do you care?" She stares hard at Abigail. It won't work - Eponine won't take Abigail's help if Abigail can't acknowledge the wickedness in Eponine and accept it, rather than immediately try to change it.

That's why Susan's currently bleeding out on a street corner and Eponine is stood still spattered with the girl's blood.