About two months ago, what looks similar to bruising appeared in Caesar's back neck folds. At first I wondered if it could actually be bruising as he and his sister sometimes bite each other on the neck in play, but the marks are straight and all follow the crease of his folds. They don't go around the neck, only on the back of the neck/top of his shoulders. I have waited for them to fade, but they haven't gotten better or worse for that matter. They don't seem to hurt him at all or cause him any discomfort in the way a bruise would. I have never seen this before on a Sphynx and while I'm really not concerned, I am wondering what it could be. I tried to take a picture of it with my macro lens, but it wasn't easy to do with him not sitting still! I hope it's not too hard to see in the photo. The little brown spots are freckles. I wish I had a before shot, but as I don't all I can say is there was no blue on him at all! Also, these are definitely not like the occasional spot that shows up later... these are all in the creases only.