A sever head blow is likely to cause headaches. If you develop
nausea, vomiting, excess sleep, severe headache, difficulty in walking and balance, tremors, seizures, vision problems, ringing in ears etc then consult a doctor immediately. These symptoms develop if there is a brain injury or bleed. Otherwise this pressure will go in a few days. However, it is important to get a medical evaluation. So please consult your doctor once. Take care!