My normally healthy Lantana is suddenly being eaten up by something and looks diseased. I douse-treated it with Neem water mix and now started seeing some tiny new growth. The "bug" didn't touch my old English dogwood nearby. It looks fine. What the heck!?
Lacking a more detailed description of what the insect pest looks like that ate your lantana leaves, it won't be possible to determine for certain what ate it. Because it has put out new growth since you sprayed with Neem, that must have taken care of the problem (or possibly the pest moved on by itself). Most insect pests attack specific types of plants, so it's not unusual that a nearby dogwood would be unaffected.