Are highlights better than dye that touches scalp if I tend to break out?

Probably not. If you have a contact allergy, then minimal skin exposure is needed to induce a reaction. An Allergist might consider patch testing to determine what you are sensitive to, or if you are have an irritant reaction (in which case you might tolerate highlights better). If a component is identified, then maybe a product can be selected that does not contain the sensitizing agent. Good luck!