Questions about Frozen effect on screen

Hello , Im working on a scene effects , and im wondering how to make a nice looking frozen effect that appears when my character feels cold ,
i found some tuts about “Post process Materials” but i can only make scenes with some transparent/Distoration effects around the screen like this picture ,

and the blueprint i made is

can anyone tell me how can i make some white color images or texture on it so that looks like frost around the screen?
like the effect of BF:Bad company 2 when the character is nearly dying in the snow

Thanks a lot for answering :smiley: