Nat, I assume you are referring to a Hoya carnosa 'Krimson Queen,' right? If so, the thread below should help.

When a variegated Hoya reverts, the variegated leaves don't die. A vine of non-variegated leaves is produced, which will outperform the variegated vines.

If you do have a KQ, you shouldn't have to worry about it reverting.

If you are talking about a different variegated Hoya, let us know.

Here is a link that might be useful: KQ variegation problems

I have a Krimson Princess, the first hoya I ever bought, and it is forever putting out the solid green leaves. They're really easy to root. I used orchid moss and the plastic ziplock. Pretty soon I will have a larger green one than the variegated one!! That's OK with me, just another hoya that I will look forward to seeing bloom.

Is it possible you are over or under watering? If I were you, I would take some cuttings to root in case the entire plant takes a turn for the worse.
Beverly

Ok thanks ill keep an eye on it, i think its just because it was in a bright place in the summer so had pale green on the leaves and over witer with the lower light levels that might have affected it?