I've had this problem ever since i got my car about it being to low and scrapping on hills.. i just got it painted and its done it again.. i have the touch up paint.. and there is a scuff mark probably 3-4 inches long o the bottom part of my bumper.. what i wanted to know is what do i use to apply the paint? would i use like a brush? or roller or something or the more common sense one of having to get it resprayed?

If you think you can do it with a brush and it wont look awful then DO IT!,If you want to spray it,it will take ages and lots of prep work,sanding down the area then trying to blend the paint so it doesnt look any different.