What you are seeing are symptoms caused by the excessive dryness that your tree experienced. That includes the rough leaf edges and brown patches. It is also behind what appears to be scale insects that you are seeing on the undersides of the new leaves. Insect pests thrive on plants that are under stress for reasons such as improper light or watering.
Unfortunately, it will not be easy for you to treat the scale insects because your tree is large a has a lot of leaves. To be effective, you have to spray all leaf and stem surfaces with a solution of 5 parts water and 1 part of alcohol and a squirt of liquid dish soap. This is a very messy task because it means all the leaves will be dripping wet. If you are in a warm climate, best to do it outside. Indoors you will have to protect the floor and surrounding furnishings.
If you are not eager to take this on, you might consider just wiping away the visibly raised bumps that are the mealybugs. If you are lucky, you may have caught the infestation early enough that wiping or spot spraying will be sufficient. But don't count on it and be watchful for new ones that may emerge.
