Who does Kevin get to bandage Dana's wounds? Why won't suicide work to bring her home again?

Kevin gets a slave woman to bandage Dana's wounds.

Withpout know exactly what chapter you're referring to, I can only say that Dana is unable to take her own life and return to the present before until Rufus has raped her black great-grandmother, assuring the inception of Dana's family tree. Without this event, Dana would not exist.