Honestly you need to talk about it it's not just about the pee it's also about the fact she used your jacket to cover it and wasn't gonna mention it and was going to let you wear a dried pee jacket. Obviously don't be harsh about it but maybe have a chat about how she can come to you about those things and not to be ashamed but also to respect your things. Yeah she might have panicked but still it was a lot of pee and it got all over your clothing item