Hi welcome to health care magic... Your child having history of trauma over ear.. So yes inner ear trauma chance can be there.... For that work up done with pharynx and otoscopy examination... If needed and symptom worsen than CT scan might needed... If no significant injuries there than sometime mild bronchitis or bleeding from gum can lead blood in spit..... Conservative management with Brufen and decongestant done.... Take care According to examination further management done Advise :otorhinolaryngologist consultation for examination...