Those leaves in the buds dying is not normal and is not the plant fading.
Does the plastic have any water puddles on it or create a hot spot, like a magnifying glass?
All the burned branches are in a straight line and I would guess that row would line up with the sun's path and the hot spot the plastic is creating.
If it is getting hot enough to the point of burning them that much I would not leave the flower in that heat much longer.
A lot of your terps are burned off at quite low temps, so if she's not smelling as great anymore, that is most likely the reason.
Dead plant material inside the flower is also opening up higher chances of mold, so I wouldn't wait too long to chop.