That might be nutrient burn on the tips of your plants. Try balancing the PH to 6.7, and feed plain water with no nutrients for a week. That will fix the nutrient imbalance.
Those are trichomes, trichomes come in many shapes and size's, those would just be less desirable since it's on a leaf. You could always take a magnifying lens and take a look. If you don't have one, mind aswell invest for harvest time
Well a quick review of your diary points me in the direction of your nutrients.
I don’t understand why you are giving the plant Big Bloom when you’re still in the vegetation. Big bloom is more for flowering which higher in phosphorus specifically for the flowering stage. So stop using the big bloom and just use the grow nutrient with a balanced PH for your medium and that should fix your problem.
Good luck with your grow. Of you have more questions don’t hesitate to DM me I’ll be glad to have a conversation with you.