It's probably better to allow it to dry out and then feed - the plant will have excess nutrients that it will continue to process so it's not needing anything from the soil for a while. You need to determine WHY you needed to flush - let's say you had a nitrogen toxicity... in that situation, when you feed her again, you want to make sure you're cutting the nitrogen-heavy nutes back by at least 3/4... if you're also using additives that are nitrogen heavy, you may decide to eliminate THEM altogether until you see how the plant is recovering. Generally, when you feed again, you want to feed the other nutes at 1/2 strength but 1/4 strength of the offending nute..
Good luck!