What Do Thick White Spots On The Skin Indicate?

I thought at first, I had a built up from using matte make-up, sunscreen and liquid clindamycin. But I scrubbed, which I never do and even my dematologist did, also. We thought that because of a problem with my hot water. But something is going on. A thickening in some areas and still thick sticky dry areas, that will not go away. Two dermatologists have said I do not have psoriasis or vitiligo. I have thick white spots,where I never wear make-up or put acne creme. I hardly can go off. I need to wear mak-up with having scars, but afraid to make matters worse. Could mold do this. My lungs have never been better. My thyroid tests came out fine. Please help me.