red flat flaky bump

For about a year now I have been getting these strange things on my face. They start out as a hard red bump...like a zit...then flatten out into a big red circle and get a flaky center ...and they take forever to go away and scar my face. I went to the dermotolgist and got a biopsy on one and it came back neg for cancer lupus etc...the only thing the test showed was inflamation (inflammation) in the skin... she said she's never seen anything like it before and its not acne... I don't know what to do or where to go...she has given up on trying to find out what it is and its getting worse.. I now have two at the same time...someone help? :(