Yet when she slept that night, she dreamt a dragon dream again. Viserys was not in it this time. There was only her and the dragon. Its scales were black as night, wet and slick with blood. Her blood, Dany sensed. Its eyes were pools of molten magma, and when it opened its mouth, the flame came roaring out in a hot jet. She could hear it singing to her. She opened her arms to the fire, embraced it, let it swallow her whole, let it cleanse her and temper her and scour her clean. She could feel her flesh sear and blacken and slough away, could feel her blood boil and turn to steam, and yet there was no pain. She felt strong and new and fierce.
In context, this dream seems to be restorative in some fashion, indicating Danaerys's acceptance of the new life she is leading and her strong will in making the best of it. From this point on, she finds life among the barbaric Dothraki easier and easier. More importantly, this dream may be prophetic, indicating that through fire Dany will find rebirth.