gray/purple arm. pic included

So I was in the ER all day yesterday because my left arm turned purple-ish & mottled. My hand/fingers however are normal colluded. They tested for/my circulation, oxygen, blood clots in my arm and heart, lungs, my red blood cell count... they couldn't find anything wrong with me, so they just sent me home with a very discoloured arm. Today is day 3 and my arm is feeling very sore.. only other symptom includes: I'm feeling a bit lethargic, green hard stool, & a bit moody-but my period is due tomorrow so that might be why I'm moody. My other arm is starting to turn a bit purple on the bottom too. I'm going back to my family doctor tomorrow, but has anyone ever heard or seen this? Google just talks and blue hands, which mine is normal. It's just odd because I barely have any other symptom, I can breathe fine and barely any pain besides today when I woke up & the purple left arm is sore.