After reading your history it appears that you might have developed secondary infection over the scalp area. I advise you to not pinch or pop the area. You can apply an antibiotic cream such as gentamycin cream. Antibiotic tablet s are must such as ciprofloxacin
under medical advise. If itching is present then can take benadryl accordingly. You can take pain killer like Ibuprofen or paracetamol
or diclofenac according to the pain severity. Consult a dermatologist
to look for the exact situation and treatment of the problem.