Hey man, new to grow diaries but a fairly experienced cannabis grower here.
By the looks of your plant I've had past experiences that had similar looks to what I'm seeing from the picture.
This looks like one of two things to me.
1. You possibly could have a pH issue in your soil. To troubleshoot that issue simply water with a pH of 6.5 until you get enough runoff at the bottom of your pot to test with your pH meter if it's out of the range of 6.0-7.0 you need to correct it by only watering in the future with a pH of 6.2 to 6.8.
2. This also looks to me it could possibly be nutrient burn from feeding your young plant too much. If there is already nutrients in the soil let your young plants Roots grow into the pot to use up the food that is already in it before feeding again.
Hope this really helps! βοΈ