Your cousin should expect to be swept, thrown, locked, pushed, pulled, kicked and punched... challenged physically, mentally and emotionally.
If the teacher is good she should also expect not to get hurt often. Maybe one minor injury a year .... jammed finger or tweaked ligament in the wrist from a lapse of focus while striking (it happens), bloody lip or nose from a training partner who lost control for a second, ect., etc.
Sore muscles and bruises will be common.