All paints need to air flow to dry properly, even pro stuff takes weeks to reach full hardness. Either way using a hair dryer from a distance wont cause a problem, but it will put crap in the paint most likely!. Just make sure you dont get it too hot. If its 2K paint (pro stuff), heat will help as its a chemical reaction hence the term "curing" rather than drying, so assuming your using celulose halfords stuff your "drying".
40c-60c curing is common in paint shops, just keep it below touch hot and you wont have any problems. Its always preferable to just let it dry naturally, either way with celulose paints the thinner will still soften it when you spray the colour, which is why its crap.......2K primers / clearcoats are a solvent barrier once cured.
Cheers,
Si