I suffer from basil migraines, but every now and then i'll get a frontal one? Should I be on preventive medicine?

Depends... On the frequency and severity of your migraines. Typically, preventive meds are prescribed for people having more than 2 migraines/month. But other factors are weighed as well including how disabling they are and the side effects of potential meds.
PREVENTIVE MEDS FOR. Migraines are prescribed to decrease the frequency of migraines. It may be a good thing for you depending on frequency and severity, so talk to your doctor about it please.