Jackthehat,
You sound like me! I tried Rogaine Foam for a month and my sensitive skin couldn't take it. I still get the occasional red blotches, scaling (psoriasis? eczema?) on my scalp. In fact, the day before my most recent HT, Dr. Paul noticed a couple on my scalp. He gave me a heavy dose of Prednisone the night before and it went away the next day before the surgery. Prednisone is effective but has some nasty sides. I was one it for over 2 months post-op. But he did say that these patches could affect growth.
So yeah, go see a dermatologist asap. But in the meantime, try some topical hydrocorstiones on 'em and see if that helps.