About plants ..

In my experence they don't unless its mild. most of the leaves will die and fall off.

Yes, yellowing can reverse, but if there is any dead spots, that will not recover. Also, possible the plant will shed it if it is too damaged.

Most macro-nutrients (such as nitrogen and phosphorus) and micro-nutrients (such as iron, magnesium, and manganese) regulate leaf coloration. Plants with inadequate nitrogen or sulfur can have an overall pale green appearance, while those deficient in phosphorus can have lower leaves with a purplish color.

https://www.growweedeasy.com/cannabis-symptoms-pictures Here you can learn to self-diagnose. Problems/Solutions explained.

Depends how it was corrected and knowing what form of nitrogen you add back. Nitrogen comes in different forms and understanding each type and how it interacts can help in future with diagnosis of nitrogen deficiency. Nitrite, nitrate, ammonia, urea, Won't bore you with details, nitrogen is highly mobile in plants but in the soil ammoniacal nitrogen is not mobile and binds aggressively and does not leech readily. When you flush one will wash away all the mobile nitrogen in form of nitrates and leave behind ammoniacal, When it comes to nitrogen breakdown of a nutrient solution, it's crucial not to exceed 30% of the total nitrogen as ammoniacal nitrogen. Higher levels can lead to toxicity, severe damage, and even plant death. Because of similarities in cal mag deficiency it can also be very difficult to distinguish from nitrogen deficiency and a cal mag problem give the similarities thay can form, making it vital to make sure the diagnosis comes from a place of logically deduced reasoning. Not just a hit and hope. While both nitrogen deficiency and a calcium-magnesium (cal mag) deficiency can cause yellowing in leaves, a nitrogen deficiency will typically present as a more uniform yellowing across the entire leaf, starting from older leaves at the bottom of the plant, whereas a cal mag deficiency will show yellowing primarily between the leaf veins, often with distinct brown spots or discoloration appearing first on younger leaves. Key differences: Affected leaves: Nitrogen deficiency usually affects older leaves first, while cal mag deficiency often shows up on newer leaves. Yellowing pattern: Nitrogen deficiency causes a more uniform yellowing across the leaf, while cal mag deficiency shows yellowing mainly between the veins. Other symptoms: Besides yellowing, cal mag deficiency may also lead to leaf curling, distorted leaf shapes, and brown spots at the leaf margins. Good luck with your situation.

Only of its a lack of chlorophyll then should return. If it has canabalised itself for the N needed then no.