The skin on the face just just super sensitive - my daughter tends to be rashy on her cheeks too, especially during the summer months when shes got sunscreen on most of the time. I, too, have used a variety of sunblocks - and have come to the conclusion that it doesn't really matter what I put on her (from top of the line, baby boutique all natural sunblocks to the sensitive skin one's sold at Target), her cheeks will get rashy from it - which, frankly, is better than leaving it off altogether and causing sunburn!
After she's had sunscreen on, I ALWAYS give her a bath (or wipe her face with a warm washcloth) with gentle soap and make sure to not let her go to bed with anything on her face. After the bath, I lotion her from head to toe with Eucerine lotion (the type in the tub, not the bottle - its creamier) - and once that has soaked in, I I put over the counter hydrocortisone cream (not the ointment, it never soaks in and attracts fuzz, hairs, etc) on the rashy parts of her cheeks. It does the trick! I will also often use vaseline on her cheeks after the hydrocortisone if she seems excessively red, dry, or irritated.
I too have been prone to rashes my entire life. From prescribed steroid creams to home remedies, I have found that often the most simple, over the counter treatments do the best!