On watering, it's always watering...
You need to water right, not just on time but the right amount. If you do it like I said and it gets better that's it! But if not, that is still how you should water and not doing it right will end badly.
Before you start playing chemist and adding or cutting things, unless you water right, you won't be better off. You'll just have a plant with a lot of things wrong.
Always fix watering first (well, maybe not first, if it's on fire, that would be first...)
Just warning you, no matter your logic, unless you want everyone in the community expounding on veg and flower for pages, bottom line, germinated straight to vegging, flip to 12 is 1st day of flower. believe me, ive made that mistake, not just once. No seedling stage.