When using the wet application techique, this is normal. The fog is the result of the alcohol/water solution evaporating from beneath the plastic. The water vapor that is produced results in a hazy appearance for several days. The haze will clear as the vapor dissipates.
We have found that the wet installation yields the best-looking installation with the least amount of difficulty in most cases. On larger headlamp pieces, bubbles and improper alignment of the material are far less likely using the wet installation method. However, on smaller pieces, such as fog lamps, the dry installation method is sometimes easier. This is especially the case if the lamp is spherical in shape.
It is absolutely imperative that a hairdryer or heat gun is used in this area to seal the edges. The heat serves two puroses. First, it helps evaporate the remaining alcohol/water solution from under the edges, and second it makes the plastic more pliable so that it can contour to the shape of the light. Be careful if you are using a heat gun to warm the plastic. It takes only a small amount of heat to apply the material. If you apply too much heat you can damage the surface of the plastic.
The removal process is just a matter of warming the plastic, and peeling them off. They will require some muscle to get them off, but they normally peel off without any residue left on the lens. If any adhesive at all remains behind, it may be removed by simply rubbing it with your thumb. The adhesive will then ball up and roll off.