I constantly deal with a sharp prickling sensation when slightly too warm, very painful and causes red dots. Could this be associated with fibro?

My doctor was confused when I told her about this and showed her pictures, she suggested a heat rash but the dots aren't raised, and they go away within seconds once the prickling stops. I'm just wondering if anyone else deals with this and if it might be something do to with fibro.

Explanation of the sensation: If the temperature raises just enough (usually 2-3 degrees above 61F) I start having this awful painful prickling sensation under my skin, like I'm being stabbed with a bunch of thick small needles. Maybe 10 seconds after the prickling starts, red dots start to appear all over my skin. These dots are completely flat, no texture at all, like someone just dotted my skin with a red sharpie. I turn the temperature down as soon as I feel the prickling start to come on, so it never lasts more than a minute or two at most. If I'm in the shower then I turn the water cold to make it stop. When the prickling stops, the dots start to disappear and they're gone within seconds.

Someone has also suggested MCAS, but that doesn't seem to fit the bill either. Both my doctor and I have no idea what this is so she doesn't know who to refer me to. She says it might not be able to be treated since it seems fairly superficial, but it's so awful, it hurts so bad, and I really wish I knew what was going on so it could be treated. Lyrica and nortiptilyne have had no effect on it.