A week ago I saw on my rear bumper a small area with a black spot, I thought it was some dirt. I tried to wipe it and realized that my Granite Green Paint was missing!! I must have damaged it a couple of days ago when I was unloading some larger boxes. The size is approximately 1/8" by 1/4" and I saw the black plastic from the bumper. I just bought some touch up paint from the dealer today. Any suggestions on how to carefully fix this spot??