hi had a bump and as a result ended up with a blue bonnet on a white mk2, it wasn't the best of bonnets but to say it was my first time spraying anything i thought i did a damm goo job!

but i got carried away and ended up giving it 4 coats of primer and 6 coats of alpine white and although i did sand the primer smooth i have been left with a grainy bonnet. it's got a rough finish because of the spraying, how can i smooth this out to end up with a slick finish? my dad said get a bit of wet andd dry on the go and lightly sand it then give it a good polish but i dont want to destroy my fantastic work

!! what do others do, and is my dad off his rocker or is it sence?
cheers
chris