Opal Color Play

I have 2 kittens, a boy and a girl. They're both really young (couple months old). They're litter box trained and had never had an accident until...

Last night, the male kitten, Harley, was playing with Opal. I guess he played too rough b/c she bolted across the house and hid behind the couch. All of the fur on her body was standing straight up and she was panting and shaking. I thought she was having a heart attack or something. Then I noticed a streak of pee across the wall. I guess she lost control of her bladder when she was running behind the couch haha.

We have a tan color flat paint on our walls. It's going to be impossible to get paint to match it exactly. Is there anything that will get it off? I tried cleaning it with a damp rag last night. Didn't work.
Like I said, we can't paint over it without painting the entire living room. We can't get the paint color to be matched 100% exactly to what it is now.