Beardie scared of outside light

[adubbs92]

Hey guys, first time beardie owner here. My dragon is about 4-6months old. For a while he would randomly puff up and beard go black and i didnt know why. I figured out he only does it when i have my bedroom curtains open. My room is usually dark other then his heat light and uvb light, and my computer screen. I feel bad when ever i open my curtains cuz i dont want to scare him, but i also want to get him used to them being open. If i leave him with the blinds open, he hides in his log house. Am i doing this right? what should i do to help spike not be afraid of the light