Brief Answer:
more information is required

Detailed Answer:
Hello,

a bump to the head could be - and usually is - a harmless accident but it could also be a pretty serious and even fatal one. The more serious accident usually share some common characteristics. I'll mention some of them right now:
- loss of consciousness: if you loose your consciousness after a head injury then this is a very good reason to seek medical help.
- loss of memory: usually of the moments before and/or after the accident. Another good reason to visit your doctor.
- patient who uses anticoagulants or antiplatelet drugs: because such patients are more prone to internal bleeding after accidents.
- neurological symptoms like tingling, loss of sensation, loss of mobility, sleepiness, vomiting, etc

If you had none of the above and you just hit your head somewhere then you can only take care of the wound (if there is any) and the bruising (if there is any too). Unless a wound is very dirty (soil, dirt, etc) or too deep then there is no fear of an infection because the head blood supply is abundant and won't let an infection develop so easily. The bruising can be dealt with ice packs for the first 24 hours. Apply the ice packs after wrapping the with a towel and let them cool the injured area for 15-20 minutes. Then take them off and apply them again in a couple of hours.

I hope you find my comments helpful!
You can contact me again, if you'd like any clarification or further information.

Kind Regards!

---