Stumpr beat me to it! That's where your moisture is coming from. Notice that the cover (that you had to drill out in order for the HID bulb to fit) was sealed with an o-ring. Now you just have a little rubber grommet in its place. Dry it out and put a bead of silicone under your grommet and you'll be good to go.How well did the rubber grommets seal in the back of the cover? The way I did mine they were tight and covered the hole I had to drill perfectly. The best thing to do would be to pop your headlights out, let them dry out then reseat the grommets with silicone. Let the silicone set then reinstall.
I don't have a shot of my covers with the grommets installed but if the grommet doesn't properly seal against the inside of the cover you will get moisture in the housing for sure.