Nits are usually easy to treat, there are different concepts, notably with Isopropyl myristate and cyclomethicone solution (trade name: Full Marks Solution®), Dimeticone 4% lotion (trade name: Hedrin®). Coconut, anise, and ylang ylang spray (trade name: Lyclear SprayAway®). Malathion 0.5% aqueous liquid (has various trade names). Only treat affected contacts (last 6 weeks), but not unaffected family members.
There should be rarely a need to contact your doctor.