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 tablets
are must according to culture and sensitivity such as ciprofloxacin
under medical advise. If itching is present then can take benadryl accordingly. The best thing is to go for culture and sensitivity of the pus.