Henna on hands?

my daughter had a school fait today and returned home from school with henna pattened all over her hands and nails. this has made me very cross, as 1:they didnt ask premition...2: she could of quite easily came out in a reaction and 3:with out sounding racist, i dont want my english daughter being tattood how a pakistani is,. we dont make them do english stuff so why do they feel they can do this to my 5 year old daughter.were taught to respect there religion ect so why cant they respect mine? its all over her nails and hands and its not even a pattern, more like a scribble all over and smudged. i have a family occation coming up at weekend and she is going to look a state as it wont come of and has stained very badly. im going up the school tommorrw to complain, is a school even aloud to do this. and how can i get it off? ive tried everything, it looks aufull and looks like she has just drawn all over herself