Hello,

The bruise is definitely due to trauma to head in that area.

Trauma could have hurt any nerve or frontal bone itself. It's important you take x.ray of skull. If there was fracture to you is frontal bone, there could be imbalance in intra cranial pressure due to fluid imbalance.

I suggest you visit an orthopaedician, and take an x-ray of skull, in particular of frontal sinus. The surgery will be putting nail through fractured bone.

Thank you.