I have had the same problem since I was about 15.
I have red hair and very pale skin so marks and scars from bad spots can be seen quite easily, especially on my forehead.
Recently, my flat mate let me try her Simple 'Kind to Skin' Smoothing face scrub, and it was so good I splashed the 4 quid for the bottle.
It gently takes away layers of your skin to reveal the new, healed layers. My red marks have started to fade and my forehead feels a lot smoother. It's only been a couple of weeks of course, but I reckon in the long run it'll have a great effect on my skin.
I recommened it to everyone - SIMPLE KIND TO SKIN, SMOOTHING FACE SCRUB
Use it twice a week.
Hope this offers some improvements for you.