If you used the rattle can self-etching primer, I would take it all off and use some out of a air spray gun. To do it right, you really need to find the system of paint you are going to use and then get the self etching primer and filler primer that are compatible with the system. That way, all the chemicals will bond correctly and you will have a really nice paint job. My experience with rattle can etching primer is that it sucks. My .02.