Strange Skin Issue? - Tiffin,OH

No, idea, but I'd give serious consideration to calling the doctor since it came-up abruptly and hasn't gone away.

None of us can tell you what it is without medical training and a physical inspection. Nor can we tell you to worry or not, but I, too, have 4 year-old with all kinds of strange things on his skin. Because of my own medical history (cancer) and his sister's recent MRSA experience, I tend to be a little quicker to call the pediatrician for my own peace of mind and their health.

has he had a bath since then? It might be marker or something like that. If not I don't know. I have two 5 year old boys and a 3 year old boy, and they are always coloring on themselves if I don't watch out! : ) If you are concerned you could ask your pediatrician.

Take him to the doctor. Could be allergies or a reaction to something or a skin infection.

Check with your doctor but my child had hand and foot when they were young and it looks like the child has been slapped across the face.
It didnt hurt them but it is contagious.

I would probably take him to the doctor just for your own peace of mind. My son is almost 10 and he had a strange looking rash and streak on his arm about a month ago. He did complain about pain with it as well, no itching, but pain. We took him to the doctor and it was some form of a skin infection. They game him 2 topical creams for it and had us give him Ibuprofen for the pain. We were cautioned to especially watch the red streak as that can sometime mean blood poisoning. Within a couple of days of using the cream, it was completely gone. Hope this helps!