Hey 👋
Definetly no issue caused by pests or bugs. You burned your plant pretty much as far as I can see.
How is the PH of the plant ? I see extremely purple stems, which indicate nutrient lock out. In this case your plant will not be able to consume anything, eventhough she has enough in the soil.
I would suggest as follows:
- check PH
- adjust PH level to ~6,2
- check also EC
- adjust EC to maximum 1,5
If you do not have something to measure, no Panik.
In this case water them with plain water only. If it gets worse you could think about flushing out the excess salts.
Hope this helps!
Good luck and enjoy your journey 👊🖖🍀