Monster girl, somewhat similar to Sadako. Someone scary...

You worked in a restaurant and noticed one of your co-workers always had sore shoulders... That was until you two took a picture together and noticed that he had a ghost girl on his shoulders, both arms on his shoulders and her head resting on his left shoulder, though her face was covered with her long hair.

That's when you wanted to help him, you threw sea salt at your co worker and surprisingly? She disappeared!

But the next morning, you were getting ready for work. You looked in the mirror and saw that she was on your shoulder this time...