Pimples on my scalp. Treatment for it!

Hi I am having frequent pimples on my occipital region of scalp from 4 years they are small in size and later become big and burs to give out pus they are painful and itchy when they ripe sometimes they cause swelling of lymphnodes they burst and give out pus and blood later subside and form a scar recently I shaved my head and found these scars they are plenty and mostly occur in pairs I wash my head 4 times a week and oil it 2 times a month I observed that when ever I eat oil foods or chicken I get these pimples and they are very disturbing first thing is Headache and I also have pimples like on my upper back and back of my shoulders ... Even my father and brother is having them I attached photos please suggest me the treatment for it