There are no conclusive solutions for spray burn. If the leaf is over 50% damaged, then it should be removed as it is no longer useful to the plant.
Spraying while the light is on will result in burning off the leaves as the light magnifies the droplets of water, therefore it's best to spray just before the lights turn off for the night.
Environmental fluctuations can also cause the exudation of water droplets on leaves (similar to sweating) and can burn the leaves when the light is on.
If an acidic spray was used, consider diluting it for any follow-up applications.