Opening it would require baking the lights, in order to melt the sealant. With doing this there is a high risk of cracking your lights, or warping them. If you decide it is worth it, remove your lights, and bake them in the oven for about 20 minutes. Work you way around the edge and pop it open. Once you remove the fog, rebake the lights, and try to replace the factory sealant the best as possible, and then silicone and openings, and also along the crease.