Once you burn your plants with sulfur, the damage is done. there is no fixing it.
In the future make sure the burner is off long before your lights come on.
Here is some useful burner knowledge. pm me if you have questions.

I have used sulfur burners for years and if you follow a few guidelines they work great.
In all fairness, prevention is key.
Good mold mildew prevention is as follows:
*Good ventilation
*Keep temps from fluctuating, especially at night. High temps and high humidity are all bad.
Low temps at night and high humidity are also bad news.
*Keep humidity in check using fans or dehumidifiers try to keep humidity below 50%

Sulfur burner guidelines.
*Make sure to begin the burn cycle at least 1 hour after lights are off to prevent leaves from absorbing the sulfur through photosynthesis.
*burn in 1/2 hour increments (1/2 hour on 1/2 hour off).
*make sure the burner is off at least 2 hours before the lights come on.

Failure to follow the last guideline is a good way to begin hating sulfur burners.

If you allow the burner to continue its cycle too close to the time when your lights come on, you risk serious plant damage.
Any residual sulfur present when the lights come on can be absorbed into the leaves once photosynthesis begins.
Since sulfur is toxic to plants, you can and will burn the ever-loving-sh*t out of your plants if the burner runs its cycle too close to lights on.

hope this helps...