Welcome and thanks for posting your query to the forum.
It seems from your problem that you have the problem of "Acne
keloides". This condition is typically seen at the back of neck as pimple like bumps. There is itching and pain over same which leads to repeated touching or scratching the area.
The black scabs are formed due to repeated scratching. The most important point to tell you is to stop touching, pinching or squeezing the area as can lead to further aggravation of the problem and secondary infection.
For the betterment you should meet a dermatologist
who can cauterize the area for best of relief.
Hope these informations are helpful.
"Wish you good health"
Dr Sanjay Kumar Kanodia
MD (Dermatology & STDs)