Odd red marks on legs when exposed to heat

19 AFAB

Doctors have been redirecting me whenever I ask them about this, so I thought I might see if anyone here recognizes the issue. My skin is normal most the time, but when exposed to heat above 70° my skin will flush, like all of my skin. If I take a warm shower or sit with a blanket over my legs they'll get red and blotchy as well as really stiff, when I bend my leg it hurts, I also see this on my ankles as well, but not my shoulders, sometimes I'll see it on my wrists but they cool down easier.

If it helps at all, I grew up in Colorado and often was outside in the cold to the point of my fingers and toes were numb and hurt when I went inside, not sure if it relates at all.

Please let me know if you have any guesses as to what this is so I can go to the doctor with some idea at least. Also all my medications I am currently taking I've taken after I started experiencing this so it's not medications, I also develop migraines when I'm too warm as well, which I'm taking medication for. (70°F or over is too warm)