Any severe or radiating pain, such as the one you describe, needs to be checked out by a doctor
as soon as possible. I would recommend that you see your primary care doctor
right away. If you cannot get in to see your primary care doctor, I would recommend a quick trip to the emergency room or an urgent care center for evaluation.
I say this because I am concerned about the "bad pimple" on your face and this new pain which seems like it is worsening and perhaps moving down your neck. A simple pimple should not cause pain in the neck. On the other hand, if the pimple has served as the source for a more serious skin infection, called cellulitis, then this could cause radiating pain. Other symptoms of cellulitis would include spreading warmth and redness around the pimple.
This condition needs to be ruled out because a cellulitis infection on the face could potential be quite serious, even requiring intravenous antibiotics.
A doctor can quickly examine the affected area and determine if you are developing a serious infection. Even if not, they can still help you treat this bad pimple that you have.
Good luck, and I hope you are feeling better soon!