I'm sorry I can't help with the make up issue, I am having the same problem with accutane and foundation :\ Never thought I would ever have dry skin but man, as soon as I put on my regular foundation (MakeUp Forever HD) I was like holy crap, I look flaky and awful. I will say though, that when I changed from Cetaphil SPF 50 moisturizer in the morning to La Roche Posay SPF 60 melt in moisturizer, I am noticing a different. It feels more moisturized. La Roche Posay products are awesome.
If you find out anymore about this, let me know. My make up is till looking funky.