If you hit your head really hard or if you have drawn blood, then I think it is worth you seeing a doctor about this, even if it means going down to the emergency room.
Chances are you are fine, as the skull is designed to protect the brain from injuries such as these.
However if you have concussion this can lead to some unpleasant side effects, and this is when it would be inadvisable to sleep.
In order to tell if you have concussion check if you have any of these symptoms:
- Headache
- Confusion
- Fainting
- Memory loss
- Nausea or vomiting
- Ringing in the ears
Again if you have any of these symptoms I would advise going to the doctors or hospital to have yourself checked out, as it is better to be safe than sorry.
Even if you feel you only experienced a little bump, I still feel a doctor if the best person to tell you when it is safe to sleep.
If you really don't want to see someone, then make sure you have someone with you when you go to sleep to wake you every few hours and check for signs of concussion.
A head injury can be serious and if you have an internal bleed the symptoms may take up to a few days to develop. In cases such as these, where you are unsure what to do, it is always worth seeking help and advice from a medical professional.
