My guess is you have two different things going on... One, it appears something is munching on the leaves. Two, the plant may not like what you're feeding it...
If it doesn't get eaten... it will probably be okay... Probably not that big of a deal...
Looks like leaf miner maggots. Ive been told sprays won't work. I have never had this problem personally before and I am not a fan of neem oil, but I have been told if you water in a low dose of neem oil it will take care of them
No I wouldn't dismiss it either. I'd try to get a handle on what's chewing at the leaves first. Try to find the sorce of the insect . Maybe some thing like "Bang" to get the leaves in a healthier state. A different mix of nutrients can get tricky - Maybe using less to see effects.
What type of soil mix did you use? Sometimes store bought potting mix can have hatchings of sorts of bugs and infections. Try sticking to sterilised mediums, a clean enviroment makes for a clean plant.
Id say get the magnifying glass out and check for eggs under the leaves Of whatever it is. Kinda looks like caterpillars to me, if it is you should be able to find them if you look. Caterpiller sprays are pretty cheap if it is them.