Physicians that treat skin problems can be primary care physicians such as your family doctor
or dermatologists. Pimples near the hairline can be acne (which does occasionally re-appear in adulthood), or other skin conditions such as seborrheic dermatitis. Seborrheic dermatitis is a skin condition which typically causes pruritic (itchy) skin that can be red, scaly and flake off in the form of dandruff. The scalp or near the hair line is a common place to get it. The cause is unknown, but it is thought that the skin which has a high concentration of glands that secrete sebum (a natural human oil) can get irritated by stress, a fungal infection, or a cause that is not yet identified. Treatment is very patient specific and would need to be selected by a physician. Options will include special shampoos, anti-fungal creams, or steroid creams. I suggest that you schedule an appointment with your primary care physician
to have a look at your pimples/rash near your hairline. He or she will be able to examine you and determine what you have and if you need treatment. If the diagnosis or treatment are not straight forward, you may need a dermatologist
referral. Good luck.