So since chameleons are reptiles and do not (obviously) sweat, turning a fan on won’t cool them (unless the enclosure is wet and it does via evaporative cooling but at this temp I would not recommend this). There are things you can do immediately to cool your enclosure down like putting ice packs on the top of it, and most simply, turning on your AC (if you have it). Check this video out:
Tips for cooling off your chameleon in the summer