Is formaldehyde bad for you if it's in a nail polish/hardener?!

Formaldehyde is toxic and carcinogenic... and by the time your nail hardener has set most of it has evaporated into the air. So the biggest risk is breathing the fumes when you paint your nails. But put it in perspective... it's not a huge risk, it's not much more risk than breathing fumes when you fill your car up with gas (petrol).

Yes. Compared to shampoo, deodorant, soap, perfume, and the tooth paste it is just as bad. We cover our bodies with so many poisons it's a wonder we have lived this long. It is bad for you but no worse the other items mentioned. Bambamit's answer is good also.

Nah, not enough that would hurt you! Your be fine as long as you are well ventilated and not around it all day,