Welcome to HCM Forum,
I can understand as a parent how u must be feeling after going through through history written by you.
There can be chances that
1)She might be having school phobia
- where she might be afraid of going to school,might have anxiety
after going to school - so there is avoidance behavior.If forced to go to school she might become aggressive.( this possibility can be there if such behavior is persistent only related to going to school)
2) Another possibility that of personality problem (can only labelled after a8 yr age completion) which can be manifested by stubborn,threatening,attention seeking behavior,demanding,head banging
behavior.( happening not only for time of going to school but also other time. )
Both kind of problem can be treated by medication and child-parent psychotherapy
.This will help to improve her academic performance and if personality problem then improve as person being- build her life in positive manner.
So first take her toward general practitioner for Lump on head treatment.Then take her to nearest good psychiatrist
who can asses in person and definitely help to resolve this problem.
Hope it helps.