Before She Says "I Do" - #XOXOConfession

Kate screwed up many years ago and never thought it would come back to get her.
She especially didn't think anything of it on her best friend's wedding day.
But she didn't realize the consequences for her mistake until it was almost too late.
Is there any way for her to fix it in time?
This is for the #XOXOConfessions contest going on. Reads and votes are highly appreciated! Thankssss!!!!!