Bullying in Schools

Salam Alaikum

If there is anything a parent fears the most, it's the bullying at school and what damage it can do to your child.
When my eldest daugther started in reception, she got bullied to the extend that she completely broke down one evening (I had no clue until that very moment). I got in contact with the teachers and headteacher but not much happened than warnings given to the kids involved. After several attempts to get something done, but without results, i decided to change the school and Alhamdulillah since then everything has been going really well and i've now got 3 kids in that school
Or so I thought! A few days ago, she came home and told me that some of her classmates had said she had a funny looking face, that it was different.. When I asked her who had said so and why, she refused to answer and kept saying she couldn't remember.. And ever since, she has been quite fragile, she's over sensitive and has such a temper, not like her at all.. as soon as she comes home she's like a tornado SubhanAllah
Then this morning we arrived early at the school.. She went to the other side of the school, so she could put her packed lunch in the lunch hall and was gonna come back straight away... I was standing at the front of the school with the other 3 and some other parents and thought she was taking alot longer than usual, i didn't put much into it, as she's such a chatterbox and most likely had bumped into one of her friends... Then suddenly i see her coming running towards me with tears in her eyes and the headteacher was following her. She grabbed me and completely broke down, whilst the headteacher told me she had been subjected to some verbal abuse, he had taken care of it and the boy was banned from the playground.. He didn't let her speak at all and afterwards she didn't say much, other than the boy was chasing her... I didn't want to completely ruin her day, so got hold of her friend and got them chatting, aswell as her teacher said she'd have a look out for her..
It completely broke my heart to see her in that state and it has left me wondering what else is going on at school? can it be the fact that she's getting bullied again, hence taking her frustrations out on us, the rest of the family??
I'm gonna get her dad to take the other siblings somewhere, so I can have a proper one to one with her and get to the bottom of this.. She's so sensitive as it is and it has become appearant that she doesn't like her skin  colour at all :( Their dad is an Arab, whilst I'm European, so the kids are all mixed race, however my eldest is the only one who has darker skin and hair, all the others are blondes.. She has made a few remarks such as "i want to look more like you and my siblings mummy" or "why do I have to look different than you?" It's heartbreaking, but regardless how much you explain it and tell her how beautiful she is, she keeps looking down in herself..