Twins in the Dutch cold.

Just start again...........this is not a nitrogen issue , it is an issue of poor genetics. Autos will not reveg, no matter what you do to them.

i'd wager you got a little fertilizer on the leaf and it resulted in what you see. important thing is it stays isolated. if it doesn't expand it;s more certainly a drip like i suspect or just some early imperfection. could be an early leaf blemish which are far more common and often don't show later, so not much concern. those 3-bladed leaves are 'early' leaves.,, even the 5-bladed seem more prone to blemishes.

yep, found a little bastard thrips today, they are here, sprayed the ladies with neem oil, water and soap towards the end of the day today.

See there's a bit of a shine to her. Can't see your TDS or what you used. But, had little to much N in veg. But, nothing that would of caused harm. But that biobloom. Does it not need some grow with it. I know it says it has a small amount of N. But, you are entering another phase of growing. So, N is needed. She looks really well.. As for defol you are still not into pre flower. So, see the big fan leafs. Id get rid of them. As she goes into pre flower you don't want your energy been pushed into making bigger fan leafs. Have a look at this. You don't have to go the whole hog. But, do remove some of them bigger fan leafs. Making sure to leave 2 on top of each node to draw in energy...(fan leafs im talking about) also Any at the very end of your plant that's not blocking out light can also be left. Makes for very interesting read. Also, as you enter flowering a bit of silica will make for a stronger plant and has lots of other benefits. Here's the defoliation link. Just read and you can apply a small bit to your grow but, you'll get the jist of how important defol can be with fems....See there's a bit of a shine to her......https://www.growweedeasy.com/nebulas-flowering-stage-defoliation-tutorial....... If you need any more help regarding anything or more on what I said. Feel free to DM me or anyone here who replies to your answer with info that helps you. Good Growing pal