before you stick your light in the oven, I've done a fair bit of research on this because my right HL is crystal clear and my other is foggy as anything with condensation inside. 200 degrees is Fahrenheit so put it in at 90-100 degrees Celsius until its warm to the touch. Once you're all done whack it back in the oven to warm the glue and take it out and clamp it together for a while to guarantee the seal.
Remember to also put something in the oven under your light to prevent it from melting to the oven rack. Use hardwood timber or something like that.
I'll try the hair dryer tomorrow but i think the damage has been done. I've also read that silica packets (from shoe boxes) are good to draw the water out.