Personally I'd be having it apart and giving the whole thing a good clean out, just like anything that draws air through it hair dyers also draw dust and fluff through them which eventually either restricts the air flow enough for them to overheat or coats the thermostat so it can't operate properly.
However, if you are not 100% confident about taking electrical equipment apart then don't try and do it yourself, either give it to somebody that can do it safely, or replace it as TB says.