4 yr old all of a sudden refuses to wash hair or wash but will play in a bath....if I go near her she's hysterical, dangerous behaviour In the bath and can be very aggressive...has had 2 baths and a wash down but no hair wash for 3 weeks..... any ideas...I've tried sponging...cup...have got a foam visor which she's watched me use on her 2 yr old brother and he loves it..