I can't stand to see you all suffer anymore.

You unlock the extra hairstyles by buying something from the lumiose boutique and wearing it to the hairdresser.

I cannot confirm if you must get your hair styled/coloured a specific amount of times however. All I know is everytime I wear the hat I bought she mentions being mesmerized by me, no matter what other clothes I'm wearing.

Pic is outdated, I changed my shirt & bag.