STYLETHREAD -- LET'S TALK SHOP!

I'm not sure what's going on with your hair. Have you ever had it highlighted before? Did you use the flat iron before you highlighted?

I highlight every 8 weeks and use the straightener a few times a week and I don't have any broken hairs. Or at least I don't notice any.

Maybe it's just your hair getting used to being highlighted for the first time? If they continue to break off, I'd be concerned but otherwise I wouldn't worry about it.

Almost anytime you lighten your hair you weaken it. That in addition to using a flat iron is most likely causing the breakage.
It really helps if you use a ceramic flat iron insted of a metal, you should also be using some sort of heat protectant, before you flat iron. Biolage makes a great one called Thermal Active, and Chi also makes a great Flat iron and flat iron products.

HTH

This could works for ur proble, I recommend Pro Naturals Moroccan Oil Hair Treatment with Heat Protector, it helps strenghten the hair that's prone to breakage, splitting or snapping off, gently smoothes the hair and form a protective mist on surface against heat damage, reduces friction from brushing and helps prevent further damage, leaves hair healthy, shiny and resilient and provides heat protection against electronic hair tools. I use it and my hair looks healthy and shiny, I hope this helps u .