Frost
Rain falls off a tree and lands in your eye where it turns to frost. It turns to frost because it’s super cold outside and your body is freezing. The rain that fell off the tree turns to frost as soon as it hits your eye.
そう
しも
None
This whole description is pretty emo. You came up with this whole emo frost idea because you are a shemo (しも). An emo who goes by she pronouns.