Had the same thing happen with Krylon paint on my day cab. had to sand block the whole cab smooth again. I was really pissed. so cab still sits in primer cause im afraid to paint it. HAHA. no seriously paint terrifies me now...
so now I will sand and send to someone who can paint good..
you can sand that cab and still use it as a test cab for body work.
Oh and try rubbing alcohol and cotton balls. it may soften the primer and smooth it out too.