Problems with 98 I30 center oplique
 

I bought a 98 I30 center oplique taill light about 4 months ago and installed it....its been fine for a while but about a month ago I noticed it has flexed in the center....the top edge of the ligth has bowed out at least a 1/4 of an inch and the wheather stripping along with it...now when it rains water gets into the trunk lid and pours out when I open the trunk! I am worried that the water will eventually cause a shirt in my tails! I remember someone else had this problem a while back and fixed it somehow....can anyone tell me a way to fix this without getting a new center tail light?