just sand and spray the fender, shit get the paint color not the same with my car, haha...darker than the OEM paint, but after spray only i realize, but dun care, temporary let it 1st. when i got time wanna send the bumper for respray, then only ask the shop help me to spray the fender with the same color paint. haha...now it look weird if u view it from near, from far is ok. as long as it dun rust then ok d, hope the putty will sitck. consider 60% successful DIY only. my advice is must get the same color spray if u wanna touch up. learn from mistake...haha...