After the exposure to Terrigen Mist, Raina has got spikes all over her head, but it's merely her physical appearance. It's by no means her superpowers. In the last episode S01E17 of Marvel's Agents of S.H.I.E.L.D., Gordon assured Raina that she would soon come to know about her gift. It means the TV show hasn't revealed her superpowers yet.
Is there any official statement on this?
Is there any Raina equivalent in the comics? If yes, what are her superpowers?
As far as I know, there is no Raina equivalent in the comics. (In fact, none of the Inhumans we've met so far have exact counterparts from the comics, though some of them seem to be variations. I suspect they're holding those for the movie.)
However, it was revealed in the TV Show what her power was, at the end of that same episode:
Lincoln figures out that Raina is clairvoyant. She "dreamed" the scene with Skye and her mom and dad at dinner before it happened.
