Take your headlight out with both lights out, let it sit overnight somewhere condensation cannot get to it (in your residence). Next day, should be good to go, ensure you seal up your bulb housing. Drilling a weep hole would actually work, some aftermarket companies use a weep tube to allow for condensation to drain out.
If you plan on drilling it, I used before a 1/4" bit and went in near the headlight mount, a tad above it, should be a bulge of plastic, there is another layer of plastic roughly 1/2" behind that, so just go in slowly til a hole is on the back end and not visible on the front side.
2009 Cobalt LS XFE U74
Mods: K&N Typhoon Intake, Option Cat-Back Exhaust, Cosmo Short shifter, Maxxim Ahead 17X7's, MPx shorty antenna, FE5 Strut/shocks, Tein S Techs, Moog endlinks, Moog spring seaters, ZZP shorty header, LSJ downpipe, LNF front grille