I had the same exact thing happen! I was mortified! I've used the scrub and such for years, it's kept me acne free, but I started using the spot treatment for a sudden break out. At first it worked like a dream, no pimples! But then I got that kind of terrible rash on each of the places I'd put the spot treatment. All these little bumps, then they dried out really bad and the skin flaked off, it turned red, it was disgusting. I put tons of vaseline on it, but the thing that really helped in the end was Aveeno Daily Moisturizing Lotion (the fragrance free, anything with perfume in it made my skin feel like it was on fire toward the end!), I'm sure anything fragrance free will work. I thought it was because I was allergic to it. I'm still having a bit of dryness, I never have before, but it's very minor. That rash lasted me a week and a half, two whole weeks if you count from the first dryness to the end of the worst stuff. I really hope since yours is only on your forehead it won't be as bad as mine was!
Good luck, I'll hope for you!
don't use to many products
it might be because you are using too many products, or maybe leaving the products on too long. So your skin is freaking out, and that caused the rash. Try cutting back on the products and trying each one out on a little trial, and figure out which one works best without bad reactions