If you fed grow nutrients recently @ recommended amounts, then I'd say hold off on giving anymore food for a bit.
Read the directions on the product, it should have a recommended feed frequency.
If there's any deficiency, to me, it looks like Iron. So why?
There should be plenty iron around already, as you've supplemented nutrient and iron's only needed in small amounts.
This raises questions about your feeding habits, watering habits and possibly pH.
Ask yourself, have you been over watering? Would the plants be fine without water another day or two?
If you're a newer grower, there's a good chance you could leave it a bit longer.
People will say pH isn't important in soil and to ignore it, the microbes and plants will regulate pH themselves.
This is only a little bit true. Soil pH is still very important.
My advice is to measure your soil pH by using a soil probe, or by making a slurry. You can also buy soil pH test kits, which I prefer myself.
Test your soil.
Iron availability really drops about pH 6.5ish and up. So if your soil's pH is 7.5 or something, it probably is Iron deficiency you're looking at.
If it's the other direction and your soil's acidic (less than pH7) it's probably not Iron and could be sulphur or calcium for example.
But you need to test your soil's pH first to form a conclusion to act on.
Remember lockout and deficiency symptoms look exactly the same. They basically are the same thing, just opposite sides of the same coin.
You've already recently given veg nutes, right?
So why the hurry?
Don't start chasing your tail.
Be smart and test your soil first. Before you start adding more nutes or anything else.
Remember NPK. (Nitrogen, Phosphorus, Potassium)
All 3 will show symptoms in older / lower growth when deficient. You're experiencing deficiency symptoms in the upper growth, whilst lower growth looks pretty good.
Meaning it probably isn't a deficiency of sorts.
So first test your soil pH.
Check your watering habits.
Be sure you haven't overfed, before giving more nutes.
These three things are usually culprits for unexplained deficiencies or lockouts.
I'll include a soil pH availability chart too, so you can have a look at it.
All the best.