Neem oil will not alleviate what's stressing these eggplants, as it is only a contact insecticide (and weak fungicide in limited circumstances). Although there might be a minor amount of flea beetle damage (a common pest of eggplant, chewing leaf holes), the beetles tend not to be well controlled by such sprays as they jump away too easily. Any beetles not contacted by the spray aren't likely to be killed or deterred. Even so, beetle feeding is not the main issue here and sprays aren't warranted for this low level of damage.

The plant's symptoms or leaf curling/cupping and distortion suggest it was either exposed to herbicide residue and/or is struggling with heat stress; both are possible as overlapping causes. For plants grown in containers surrounded by paved or hard surfaces, the heat that's reflected (and radiated back out at night) not only can dry them out faster, but also impact their metabolism since they cannot keep cool enough to grow and flower/fruit normally. Roots can cease growth beyond certain soil temperatures, and pollen in flowers can die, resulting in a poorer harvest from ineffective pollination.

All you can do for now is to test the potting mix for possible herbicide contamination and keep an eye on the plant's water needs. The simplest test is to germinate some rapidly-sprouting seeds in the same soil (if you have an unused supply of it, for instance) and see if they grow normally. It's also possible drift on a breeze or from evaporation on a hot day brought airborne herbicide to the foliage, especially if any weed killer was used in the vicinity before these symptoms appeared. If a container was used to spray herbicide that was later used to spray neem or another pesticide, residues left behind can cause damage.

Plants do not heal leaf damage, but signs of recovery would include new growth that develops normally. Eventually, the plant may shed the leaves with the worst damage.

Miri