Hair irons are serious business! It's always a good idea to check them before you use them.

You should always check what surface anything hot is on before you turn it on. As much as it sucks that you had to cut a chunk of hair out you're lucky it wasn't worse.

I hope you are pulling off the new look.

now you don't have to worry about straightening them

Next time, granted I hope there will will be no next time, you could very very carefully try to dissolve the plastic with paint thinner, but try to not get it on your skin. Make sure to be far far away from your hair straightener or any other heat source though, because paint thinner is highly flammable.

Acetone will dissolve plastics, and it's safer than paint thinner. (Odds are, you already have it as nail polish remover.) Caveat: I have no idea what it will do to hair though. It should strip the oils from it, leaving you in need of one of those "replenishing" shampoos advertised with the CGI oil droplets flowing into a huge strand of hair.

Better to just cut the hair.