Not only will it be very uncomfortable to leave the tick head in the skin, but it is also very dangerous. It can become infected and leave you will more troubles than it is worth. You will need to ensure that you clean the tick head properly before you can have it removed by a doctor or within the hospital. Ignoring the tick head is only going to make things worse and you are going to have more problems and more infections than you would have normally had, you are going to have to ensure that you are safe from any further dangers by having it removed properly and correctly by a professional.
It is likely that you will never have come cross a tick head before and had to removed it, therefore you are going to have to do your bit by cleaning it with hydrogen peroxide, and if you feel as though this is something that you are not going to be able to do, you should make an emergency appointment with your doctor to have it taken care of.
There will be no initial pain until the infection begins to take action, you will experience irritation and find that it is something you wasn't removed as soon as possible.
The tick head is never left in when an animal has a tick and therefore you should not assume that it can be left in a human's. Being healthy is much more important than being too idle to have the tick head removed properly so to save your health and to ensure that you do not have an infection, it is advised that you go to your local GP or hospital to have the situation taken care as soon as possible.