I have the same exact thing!!!! lol I have anxiety & take meds on a daily basis for this BUT also I was recently diagnosed with a skin disease called Rosacea... Maybe you want to see a dermatologist to rule that out. I get blotches of red on my chest & face when I get angry or nervous... weird huh? lol it stinks! Oh, the meds for my face is call Metrogel one percent.. good luck!
Actually, there ARE some medications that can be helpful with this. I would get a second opinion if I wee you.
One class of medications that can help decrease the blushing are beta blockers. They are often prescribed to help people who have issues with stage fright, or difficulty speaking in front of large groups (ie, an oral class presentation). It can be taken "as needed" (like the morning before a big speech), or daily, for more chronic issues (like yours). One of the more commonly prescribed beta blocker for severe blushing would be Inderal (propanolol).
A word of caution, these are heart medications and will cause a drop in your blood pressure, so it is important that you watch for side effects when starting a beta blocker (hypotension, etc). Of course you need to speak with a doctor about this, my advice would be to possibly try a psychiatrist. They may be able to offer some suggestions for you.
Like I said, there are definitely some treatment options, so keep looking for a doctor until you find one who is aware of this and is willing to help you try to fix it!!!
Good luck, update us when you can!