Brief Answer:
You need to go to your doctor in person and get examined.

Detailed Answer:

Hi,

If headaches are not relieved by paracetamol, then it needs further evaluation to rule out any serious neurological problem.

As I can see, you had a head injury associated with nausea a week back, and this could complicate things further and can be a reason behind your headaches.

I strongly urge you to get yourself examined by a neurologist in person and rule out anything serious.

Moreover, headache that is not subsiding with paracetamol can be controlled by injectable pain killers.

Please consult a neurologist/neurosurgeon and get yourself evaluated properly and take treatment as advised.

Do get your blood pressure checked to rule that out as a cause of your headache.

Wishing you speedy recovery.
Regards

---