I have a fair skin. The skin above my upper lip is fairer than other parts. My skin is very sensitive, so my cheeks are always red.. So the colour difference is more noticeable.. Can you suggest any remedy to make this difference invisible..

What I suggest is using a color correcting face primer. I am also pale with a pink skin tone and I use Make Up For Ever HD Microperfecting Primer
What it is:
A lightweight, oil-free complexion corrector that enhances the skin's texture and primes the skin for makeup application.

What it does:
HD Microperfecting Primer deeply nourishes, moisturizes, and softens the skin, creating a glowing effect. Creates a protective layer on the skin allowing foundation to glide on easily and last longer.

What else you need to know:
The Sephora-exclusive primer comes in six color-correcting shades and one transparent shade.

I use the green shade because green cancels out all of the red on my face. I even use some on my neck to help blend with the rest of my body. Yes, putting on green all over my face was scary at first, but it got rid of all of the red in my face and helped my foundation look smooth and flawless! It is pricy, but, for me, this is a product I am okay spending some money on! Hope this helps!
Here's the website: http://www.sephora.com/browse/product.jhtml?id=P217906&categoryId=B70