Hi, I have exactly the same problem!
I had a job interview last week (didn't get it) and while I was being given feedback the woman mentioned 'my face colouring' twice!
I already knew I blush easily and feel like this has knocked my confidence even more.
I was on the phone earlier and found that I was going red talking on the phone to which my Dad then picked up on and said I needed to try and get over this or people won't think I'm capable when I go for interviews.
Sooo fed up right now...