After finishing the Sarthaal quest I talk to Brelyna and she cast he spell on me and I get the dialog: "I'm not really sure. I think it's just a minor miscalculation on my part. I'm sure it will wear off soon. When it does, you'll be perfectly fine, and then we can try again. In the meantime, I'll see about figuring out what went wrong."

The problem is that I'm not getting the rest of it. I've waited days away from the college and when I go back I never get:

After waiting for the spell to wear off, you can tell this to her and she will confidently state, "Exactly as I said it would." and ask you, "Now, are you ready to try again? I am confident it will work this time."

Is there a quest number for this? Or is there some other way to fix it? I'd like to use her as a follower but I can't get the dialog.

Thanks

I did that but I think you HAVE to let her keep trying, let her do it, untill you are back to normal.

if thats not it I don't know hope this helps

EDIT: I dug into it and found that there aren't any known bugs involving

what you are saying. But what I did find is what you must do:

1. Talk to http://www.uesp.net/wiki/Skyrim:Brelyna_Maryon.
2. Let her cast a spell on you.
3. Wait a few in-game hours to let the effects wear off.
4. Let Brelyna try again.
5. Wait for her to finish

I found that from da wiki

I've not only waited a few hours it's ben days and days and I never get the try again dialog.