I have pimples on my face. I think.

Sir, I have pimples on my face. It is like allergy. My skin is oily and very sensitive. I had consulted by 3 dermatologists,but it is not curing completely.I avoid oily foods,eggs,milk and milk oriented products.the pimples are not only on my face but also on head too. After taking the medicines there will be a temporary relief,but after few days the pimples are generating again. .whoever See's my face they say it is not pimples,it is allergy. And the disappointing thing is, the spot where this pimple formed continuously,there is no hair growth nowadays. I dont know why this is happening to me alone.none of my family members not have this issues. My skin was not sensitive.i used to use skin care products in the past.may be that made my face skin sensitive i think. Please help me in this problem.