If you didn't boil it, add malt, grain or hops and are using "Can top" yeast, well, I wouldn't be holding my breath, not until I am trying to choke the finished brew down. Adding a bunch of sugar is just going to make it worse. I say toss in the yeast and use it as a base line for future brews.
Before I learned to brew I was poor, sober and lonely. Now I am just poor.