Unfortunately spray paint will not cover up imperfections, it's too light of a coating. I would sand down the exterior of the bumper.. an electric sander with 230grit paper should get you done in about 10min... or a block and manual sand it, which just takes longer.. the idea is to get it level, no need to remove all the layers applied... go out and buy rustoleum bed liner spray paint and put 3 lights coats on.. done. My brawler middy is por-15 coated with that bedliner top coat and its durable once cured.... best part... i found a wide scratch from when i screwed up mounting the skid plate( whole bumper shifted on the chairs i was using... sanded down the area taped it off sprayed a couple coats, sanded down again to level the surface and hit one last coat for the final textured finish and it looks like it never happened. You will not be disappointed with the final finish.. just make sure you follow the spay directions, if you find any areas that look darker in color, you went to heavy but whats great is a quick light spray over the area fixes it, if it runs sand down and re-apply. keep in mind its a paint with sand like particles in it.. so these 2 work together for the final finish.. get to close and the paint washes out the particles which is why it appears darker and shiny under light..