My 3 yr old son has been waking up with this rash occasionally after taking naps. The rash is not raised but instead appears to look like small specks of blood under the skin?? He does not have any allergies that we know of and the rash appears sporadically, although he sleeps in the same place regularly. It will normally disappear within a day or two after first appearance. Any idea what could be causing this?

Thank you!