Isn’t the foggy appearance coming from the inside of the lens cover?

More than likely, no. Only in a very small percent of foggy headlights is the foggy appearance actually coming from the inside of the lens cover. Many people think this but in fact almost all cloudy headlights are a result of the outside of the lens cover being oxidized. In rare occurrences, however, condensation can build up on the inside of the lens cover from rain because of a broken or faulty headlight seal. The good news is that all headlights come with vent holes and when your headlights are on, they generate a lot of heat that evaporates the moisture through the vents.