Spidermite looking damage but no mites or any kind of pest?

Hi

I have 3 autoflowers going at the moment, in a 4x4 with some pepper plants and misc other plants (herbs etc).
lighting is 400watt hps 18/6, soil (a brand most of you won't know as its new zealand), I'm using Calipro nutes.
Plants are around 35-45 days old, 2 are about a week or 2 into flower and 1 is about 2 weeks in.

I've got what looks like spidermite damage to all 3, more so on one of them. I've had similar looking damage in a previous grow but didn't pay much attention to it.

I panicked and sprayed Neem oil + detergent mixture without thinking first, and it burnt the oldest plants pistils luckily it's growing through the burnt ones and should at least harvest something.
The other 2 have very "wispy" looking flowers too, something I've never seen.

Now, I've taken numerous leaves off and looked under a smartphone microscope/loupe attachment, and there is literally zero bugs or movement. There is no webs of any kind, just the damage.

I'm confused, and not sure what step to take next? I thought it might be powdery mildew but no, it looks identical to spidermite damage.

Any advice would be helpful I've attached a few pictures, 1 of the damage and a couple of the worst affected plant, i've never had such wispy flowers and i'm wondering if i've f**ked it by using neem oil, it's also pretty "naked" which is kinda odd, i have barely defoliated.

Thanks in advance

 

yep, checked everywhere :-/ literally no sign of life. it's bizarre. this was before and after the neem oil